Edit the Ticket's Service
If the chosen service is incorrect, Edit the ticket and choose the correct one.

Reassign the ticket
Reassign the ticket to the correct group using the Actions menu

Inform the Requester of the Correct Service
You probably also want to let your users 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, and copying and pasting the link from there.
- Be sure to choose the requestor in the notification drop-down
- Then click Save to send the message to your user.