You'll want to open the ticket and choose the Edit button. Then change the service to the correct service. The ticket type will automatically change but you will also need to change the responsible group to the correct group.
You probably also want to let your user know, for future reference, what service they SHOULD have chosen and here is one way to do that:
- From the ticket choose Actions > Update
- In the header of the comments box click Templates > General > Responding to users who chose the wrong service for their ticket.
- replace the [PASTE LINK TO CORRECT SERVICE HERE] with the link to the service by navigating to the service in the service catalog, choosing Share and cutting and pasting the link from there.
- Be sure to click the requestor in the notification drop down
- Then click save to send the preformed message to your user.