@scarecrow kakashi Thank you for reaching out to us.
You can use the below graph call to revoke the Refresh token:
To revoke the refresh token of the signed-in user:
POST https://graph.microsoft.com/v1.0/me/revokeSignInSessions
To revoke the refresh token of another user:
POST https://graph.microsoft.com/v1.0/users/object_id_or_upn_of_user/revokeSignInSessions
Alternatively, you can use below PowerShell cmdlets as well:
Revoke-AzureADSignedInUserAllRefreshToken
Revoke-AzureADUserAllRefreshToken
Let me know if you have any questions.