If you install Unreal Tournament III to play exclusively offline or on a LAN, you cannot simply change your player name. In addition, the campaign will not be saved.
To be able to customize it anyway, you must perform the following steps:
Step 1: Requirements
The game must have been started at least once.
Step 2: File location
A file named “Player.ue3profile” has been created in the path “C:\Users\%username%\Documents\My Games\Unreal Tournament 3\UTGame\SaveData”.
Step 3: Change name
Simply replace the “Player” with the desired new name, avoiding special characters, etc. The result would be, for example, “TestPlayer1.ue3profile”.
Step 4: Login
Now start the game and enter the new name in the “Name” field of the login box, but do not enter a password.
Step 5: Offline mode
Click the “Play offline” button at the bottom.
Step 6: Testing
Done - you can now see that the name has been applied in the lower left corner. It will also be used automatically as the default in the future.