Changing Atari Accounts on an Already Made Profile

[AskaLangly]

Okay...

So I have two game profiles, and both are online.
You have my profile and my brother-in-law's profile.
Both of us bought the game on here, and have separate CD keys.
Now, before all this, I made his game profile using MY Atari account.
Since I'm getting a new gaming rig soon, I want to do some 2P with him, but the issue is that we are both on the same Atari account; pretty screwed as I cannot edit the account name, just the password.
I cannot remove his progress (Lv27) or I'm a dead man.
Please help. Thanks.