Laura, you will want to begin by familiarizing yourself with the instructions for IRS Form 8282. That will address the legal requirements.
Typically, your Gift Acceptance Policy will have two related sections: Disposing Property Gifts & Ungifting. The later is for all form of donations when you want to remove yourself from a gift due to donor ethical issues.
As for the disposing piece, that section mostly outlines the responsibility of the gift recipient to notify your office when they wish to rid themselves of the gift. That notification should include the reason, method, and timing as well as information on how the gift was used when owned by you.
That section should also address internal notifications such as the Business Office for asset reduction purposes, and Donor Relations for contacting the original donor.
John
John Taylor Principal, John H. Taylor Consulting, LLC 919.816.5903 Big ideas; small keyboard