TOPIC: Project charter

Dear Sirs,
Can a Project charter be changed after sign-off ? Does it require a change request or just addendum?
{incase if asked under exam situation}

sure, any project document can be changed - also the Project charter.
But the change need to be approved by the Project Sponsor or the CCB appointed by the sponsor.
It is not in the authority of the Projectmanager to approve changes in the charter.