It's possible to change an existing ticket's requester to someone else. You may want to do this if someone sent in a support request on someone else's behalf. The user who you want to set as the requester must be a user in your Zendesk.
Note: You can't change the requester on a ticket that has been shared or closed.
To change the ticket requester
Select a ticket from one of your views.
Next to the ticket requester's name, below the ticket title, click Change.
Zendesk Classic: Click Edit/Share next to the ticket requester's name, then click Change.
The Requester field is displayed in the ticket properties panel.
Begin entering a user's name and the relevant results are displayed. Select the user.
Click Submit to save the ticket update.
After you've changed a requester, you can later see who the original requester was by checking the ticket's events and notifications.