cant change back to old apple id

i created an apple id with the email id example1@gmail.com about an year ago.

(i might not have verified it. I don't remember).

recently when i logged into the manage apple id page to change a typo in my name the only option was to change apple id and a button that says send verification email. when i clicked on that it says id already associated with other apple id.

i clicked on edit next to my apple id and used example2@gmail.com and verified it.

now i cant change back to the old id because it says it is already associated with apple id.