You can revoke WipeAway's access to your Google account at any time through your Google Account settings. This removes WipeAway's authorisation without affecting your licence key or your Google Calendar data.
WipeAway will no longer be able to access your Google Calendar from that point on.
Revoking access is not the same as signing out. Signing out ends your WipeAway session but leaves the authorisation in place. Revoking access at Google removes the authorisation entirely — you would need to go through the sign-in and approval process again to use WipeAway.
If you want to use WipeAway again after revoking access, simply go to wipeaway.app, enter your licence key, and sign in with your Google account. Google will ask you to grant permissions again, exactly as it did the first time.