Owners of a My Bibliography can grant access to others (delegates) to help manage their My Bibliography. Delegates can perform all the same functions as an owner.
To invite a delegate, go to the top right side of the My Bibliography page and click your user name. A drop down menu will appear. Select Account Settings and scroll down to the Delegates box. Select Add a Delegate.
A delegate must have a My NCBI account to be a delegate, and must be logged in to their NCBI account before accepting an invitation to be a delegate. See Confirming a My Bibliography Connection for Delegates.