I want to change my email to one that I have already used.

I want to change my Adobe account's email from its school one to my home one. The problem though is that for some reason, I already had a completely empty and separate account with my home one. I tried deleting it, but when I tried to change the email again, it still says it's been used. Is this a permanent problem, do I have to wait a little longer or is there a way around this? I'm worried my school will delete my Adobe.