How to change the Template Owner
For changing the usernames in the Owners field of the Template the Change Template Owner permission should be granted.
How to change the Template Owner username:
Open the Manage Templates page.
Select a Template you want to pass to another owner.
Select a new owner in the Owner field of the Template Details section.
Click the Update button at the bottom of the dialog.
In case, the user is not granted the Change Template Owner permission he will see the notification like this after changing the Owner for the Template. The updated usernames will not be saved.