My fathers iPhone 4 stopped working and I had an iPhone 4 that I put his sim in but Apple ID wrong?

[iMore Question]

We are under the same plan, thus carrier, AT&T. I put his sim in my old iPhone 4 and the number is correct but no other info transferred and I do not remember my paws for my old Apple ID. How to I resolve this problem? Also, my phone provider will not know that the phone is a different one, correct???

 

[kch50428]

http://support.apple.com/en-us/ht5787