By default, only employees with these security roles can freeze or unfreeze memberships: Marketing Manager, Manager, Zonal Manager, and Owner. If you do not see the Unfreeze button, get in touch with your administrator and ask for the appropriate permissions.
Open the Guest History page.
Click the Memberships tab, and then click the name of the membership to unfreeze.
On the top right-hand side of the membership details window, click Unfreeze.