Good Morning.

Well, if you dont want to log into each mailbox, the only other way is to go into the VM directory in the avaya IP office folder (default is : C:\Program Files\Avaya\IP Office\Voicemail Pro\VM\Accounts)

Delete the .wav file from all the user folders that you left a message for.

Once done, you will need to stop and restart th 2 VM Pro services. That would clear the lights off all the phones that you just removed the wav files from.