We support doing exactly this type of transfer. Within the manage site, there's a change ownership command. What I suggest is this:

1. Once you've made the financial arrangements, have John transfer the domain to a new profile. He'll create one with a username and password of his choosing.
2. Have him provide you with the username & password.
3. If you have an existing profile with us, transfer the domain to it. If not, change the password of the profile.
4. You MUST change the Admin contact info, including email address, to yourself. You SHOULD change the Org & Billing contact as well. The Admin contact is the most important, & is considered the domain owner.
5. The domain is now yours, and under your control.

You'll find the transfer ownership page under Profile/Change Ownership. You can use this function to transfer the domain to a new account, or to an existing Register4less.com profile. If you're going to an existing register4less.com profile, make sure to check "Move to an existing profile".