NOTICE SPECIAL MEETING TO INCREASE LEVERAGE RATIO ETCNOTICE OF SPECIAL MEETING OF UNITHOLDERS OF SLATE OFFICE REIT All capitalized terms used herein but not otherwise defined have the meaning ascribed thereto in the management information circular dated November 23, 2023 (the “Information Circular”) accompanying and forming part of this notice of special meeting (this “Notice of Meeting”). NOTICE IS HEREBY GIVEN that a special meeting (the “Meeting”) of the holders (the “Unitholders”) of units (“Units”) and special voting units (“Special Voting Units”, and together with the Units, the “Voting Units”) of Slate Office REIT (the “REIT”), which will be held at the offices of McCarthy Ttrault LLP, 66 Wellington Street West, Suite 5300, Toronto, Ontario, M5K 1E6, on December 29, 2023 at 10:00 a.m. (Eastern Daylight Time). The Meeting will be held for the following purposes: (i) to consider and, if thought fit, pass a special resolution authorizing and approving an amendment to the amended and restated declaration of trust of REIT dated March 21, 2016, as amended on March 1, 2019 and May 13, 2021, for the purposes of removing the restriction imposed on the REIT not to incur or assume additional indebtedness that would cause the REIT to achieve financial leverage in excess of 65% of its gross book value, the full text of which is set forth in Appendix A to the Information Circular (the “Amendment Resolution”); and (ii) to transact such other business as may be properly brought before the Meeting and any adjournment or postponement thereof. The specific details of the foregoing matters to be put before the Meeting are set forth in the Information Circular under “Business of the Meeting”, accompanying and forming part of this Notice of Meeting. The Board of Trustees of the REIT have fixed November 17, 2023, as the record date (the “Record Date”) for the purpose of determining holders of Voting Units entitled to receive notice of and to vote at the Meeting. Any holder of Voting Units of record at the close of business on the Record Date is entitled to vote the Voting Units registered in such Unitholder’s name at that date on each matter to be acted upon at the Meeting. To be approved, the Amendment Resolution must receive the affirmative vote of not less than two-thirds of the votes cast thereon by holders of the Voting Units at the Meeting, with such Unitholders voting together as a single class. For the Meeting, a quorum is present if there are at least two Unitholders present in person or represented by proxy, holding or representing by proxy in aggregate at least 25% of the total number of outstanding Voting Units. Unitholders who hold their Voting Units with a bank, broker or other financial intermediary are not registered Unitholders. If you are not a registered Unitholder, you will have received a request for voting instructions from your broker or other nominee. Please complete and return your voting instruction form in accordance with the directions on the voting instruction form. To be effective, a voting instruction form must be received no later than 10:00 a.m. (Eastern Daylight Time) on December 27, 2023. If you plan to attend the Meeting and wish to vote in person, please follow the instructions on the related voting instruction form to appoint yourself, instead of the management nominees, to vote at the Meeting. Non-registered Unitholders must take the necessary steps to appoint themselves if they wish to vote at the Meeting in person. Please take the time to ensure your vote is included at the Meeting. A Unitholder who wishes to appoint a person other than the management nominees identified on the form of proxy or voting instruction form (including a non-registered Unitholder who wishes to appoint themselves to attend) must carefully follow the instructions in the Information Circular and on their form of proxy or voting instruction form. - 3 - If unable to attend the Meeting, a registered Unitholder may submit his or her proxy by mail, by facsimile or over the Internet in accordance with the instructions below. A non-registered Unitholder should follow the instructions included on the voting instruction form provided by his or her intermediary. Voting by Mail before the Meeting. A registered Unitholder may submit his or her proxy by mail by completing, dating and signing the form of proxy related to the business of the Meeting and returning it using the envelope provided or otherwise to the attention of the Proxy Department of TSX Trust Company, 301 – 100 Adelaide Street West Toronto, Ontario, M5H 4H1. Voting by Facsimile before the Meeting. A registered Unitholder may submit his or her proxy by facsimile by completing, dating and signing the form of proxy related to the business of the Meeting and returning it by facsimile to TSX Trust Company at 416-595-9593. Voting by Internet before the Meeting. A registered Unitholder may vote over the Internet by going to www.voteproxyonline.com and following the instructions. Such Unitholder will require a control number (located on the front of the proxy) to identify themselves to the system. In order to be valid and acted upon at the Meeting, proxies must be received by TSX Trust Company not later than 10:00 a.m. (Eastern Daylight Time) on December 27, 2023, or, if the Meeting is adjourned or postponed, 48 hours (excluding Saturdays, Sundays and statutory holidays) before any adjournment or postponement of the Meeting. If a Unitholder receives more than one form of proxy because such Unitholder owns Voting Units registered in different names or addresses, each form of proxy should be completed and returned. Unitholders are cautioned that the use of mail to transmit proxies is at each Unitholder’s risk. The Chair of the Meeting has the discretion to extend or waive the deadline for the deposit of proxies at his or her discretion without notice. Only registered Unitholders and duly appointed proxyholders will be entitled to attend the Meeting in person. The REIT urges all Unitholders to vote in advance of the Meeting in accordance with the instructions set out in this Information Circular. Notice-and-Access The REIT has elected to use the notice-and-access provisions under National Instrument 51-102 – Continuous Disclosure Obligations (“NI 51-102”) and National Instrument 54-101 – Communication with Beneficial Owners of Securities of a Reporting Issuer (“NI 54-101”, and together with NI 51-102, the “Noticeand-Access Provisions”) for the Meeting. The Notice-and-Access Provisions are a set of rules developed by the Canadian Securities Administrators that allow issuers to post electronic versions of proxy-related materials online, via the System for Electronic Document Analysis and Retrieval + (“SEDAR+”) and one other website, rather than mailing paper copies of such materials to securityholders. Electronic copies of this Notice of Meeting and the Information Circular may be found on SEDAR+ at www.sedarplus.ca under the REIT’s issuer profile and at https://docs.tsxtrust.com/2114. Unitholders are reminded to review the Information Circular before voting. Unitholders will receive paper copies of a notice package (the “Notice Package”) via pre-paid mail containing a notice with information prescribed by NI 54-101 and a form of proxy (if you are a registered Unitholder) or a voting instruction form (if you are a non-registered Unitholder). The REIT will not use procedures known as ‘stratification’ in relation to the use of Notice-and-Access Provisions. Stratification occurs when an issuer using Notice-and-Access Provisions sends a paper copy of the Information Circular to some securityholders with a Notice Package. Unitholders may obtain paper copies of this Information Circular free of charge by calling +1 (866) 600-5869 or by e-mailing tsxtis@tmx.com. Any Unitholder wishing to obtain a paper copy of the meeting materials should submit their request no later than 10:00 a.m. (Eastern Daylight Time) on December 18, 2023, in order to receive paper copies of the meeting materials in time to vote before the Meeting. Unitholders may - 4 - also use the toll-free number noted above to obtain more information about the Notice-and-Access Provisions. Under the Notice-and-Access Provisions, meeting materials will be available for viewing at https://docs.tsxtrust.com/2114 for one year from the date of posting. DATED at Toronto, Ontario, this 23rd day of November, 2023. By order of the Board of Trustees, “Monty Baker” ______________________________________ MONTY BAKER Interim Chair, Board of Trustees, Slate Office REIT