If required, an approved endorsement can be revoked by an underwriter user.
Only an endorsement with Approved status can be revoked. If the Revoke button is not available, check if the endorsement you are working on has been approved and closed. If it is open then you may want to use the Reject Endorsement feature.
Revoke an Endorsement
To withdraw an accepted endorsement, press the Revoke Endorsement button in the View Endorsement page:

A dialog is presented asking you to confirm:

Once confirmed the status of the endorsement changes from Approved to Cancelled:

Cancelled/Revoked Endorsement
When you go to the View Endorsement page for a Cancelled endorsement, there are no options available.
Example of Cancelled Endorsement:
