When working in the Agent/Office tab of the Listings module, you have the ability to add Co-List Agent information.
If you are unsure of the Co-List Agent ID, select the magnifying glass next to the text field and search by Realtor name, office name, or office ID.
As part of these details, you have the choice to "Allow Co-Lister to Edit this Listing." If you select this checkbox, the Co-List Agent will have the ability to access the listing from their My Listings/Transactions page and make the same editing changes that the List Agent can.