Entitlement revocation is being rolled out this week. All customers should have the functionality by the end of Thursday (May 22).
When you assign the Access Revoker user level, that user should see the Admin menu in their top menu bar and should have the Identity Management page visible under it.
Managers should see the My Team card on their home page and end users should see the My Access card. Revocation is supported from those pages as documented here: Requesting Access Removal - SailPoint Identity Security Cloud User Help
If these things are not working for you as described, please open a support ticket for help.