I have read through other responses - from back in November... Tried everything. Must have at one point tried to use new email for apple id - but it won't let me do it now. Frustrating!,,
appleid.apple.com
You can track down past appleID's there and also do edits and password resets.
Did you ever get an answer?
I'd suggest you start your own thread as this OP has not been active for 3 1/2 years here.
If your question is about " "This email address is already in use" for apple ID. I don't have another account. How can I change it? " = the answer is you can't without getting another email account -- Yahoo, Gmail & Hotmail are common free email services.
"This email address is already in use" for apple ID. I don't have another account. How can I change it?
