[otrs] customer interface -ticket owner

hi, in the customer interface there is the field ówner´ for the ticket. Standard it show the username of the owner, (f.e . : abbbbb) where can i find the settings to change this to the first and/or last name of the owner? (f.e. aaa bbbb) I really cant find it , and it would be stupid to change all the agent user id´s.. thanks!