Yes, you can. By default, Unbabel will fire when a ticket is opened by an authorized agent who does not speak the language of that ticket - the Start Automatically translation model is on. If you wish for Unbabel to only initialize on-demand, you can change your Translation model on the Settings Page. With Start Automatically off, an agent opening the ticket will need to press the Translate button to launch the app and fire the first translation. This is not reversible, and all needed translations will appear on the ticket from that moment on.
Be sure to have your agent's spoken languages correctly set up before using the On-demand feature so that agents are not trying to start tickets in spoken languages.