Wrong Apple ID

You can't change the email address of the new ID to the old ID as that would be merging two Apple IDs.

If suggest you do the steps in the article below to completely remove the phone from the new ID. You can then set up the phone using the old ID.

Selling/Giving Away Device.      

See Change your Apple ID https://support.apple.com/en-us/HT202667. 

And see What to do after you change your Apple ID or password https://support.apple.com/en-us/HT204071 (supplementary to what the fist link says).

Note that you won't be able to change it to your original Apple ID. You can't reuse an email address that was previously been associated with an Apple ID in any way until an uncertain period has passed--sometimes reputed to be 30 day and sometimes 1 year. Also, I have seen that you never can use such an email address again. The last two times I saw a wait period claimed it was said to be “up to 30 days." You can contact Apple support to check out the wait period. 

You can get Apple telephone support for help using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362 Be patient sometimes Apple support is closed to immediate phone support.