[You need to have permission to do it.]
There are two ways of doing it. With one of them you can delete all messages, and the other you must delete each message individually.
Method 1:
Go to Tuvis Engage app on SalesForce:
On Dashboard tab, Click on View Report that’s inside of Total messages dash, and select the messages you want to delete
Method 2
Still on Tuvis Engage App, go to settings and click on Delete All Synced Messages.
