I wanted to change my name too. I couldn't apply for CK b'coz the name in my ECFMG record didn't match my name on my passport. So I downloaded, printed, filled and faxed form no. 182 to ECFMG. Within 2 weeks I received an e-mail from ECFMG that my name had been changed on the ECFMG record as I requested. And when I checked on OASIS it actually had changed and my problem was solved. So I can definitely say that the name change pathway thru form 182 works if you have a problem with your name.There are two ways you can solve this issue:
Pathway number one (the appropriate legal one)
Go here first
In that page you can request your old USMLE ID. (but you have to tell your old name and email exactly correct).
Then go here
In that page you request your old password by entering your old USMLE ID.
Then when you get your old USMLE ID and Password use them to log in to OASIS page here
When you are logged in there you will see immediately a link to download Form 182 (I attached it to this post you can download it from here also).
Pathway number two (inappropriate and maybe considered irregular behavior)
The other way is that you simply sign up with a new name and a new email and this way they will not recognize you as the same person as before even if with a simple name change (like one letter difference).
The problem with pathway number one is that you have to submit a proof of name change. Like a legal authenticated document such as a court order.