switching number between accounts

So, I'm currently on a family plan (I am not the primary account holder) but decided to split off and get my own account when buying the i5. I was eligible for an upgarde on the family plan and I could've taken it and then did a transfer of billing responsibility BUT instead I decided to start as a new customer. I was looking forward to a new number but I wanted to keep my old one for a little while just in case which is why I did it that way. So at the moment I have two phones with two numbers on two different accounts.

To make this short, I don't like my new number (actually I don't like the area code 424 I was issued, so it's not just a matter of requesting a new number because they'll probably give me the same 424 area code). My other phone, a 310 area code, I still have and is still active on my other phone but on a different account. Is there a way to transfer that number to my new phone? Both phone numbers are in my posession just a matter of whether I can switch the number between two different accounts. 

If not, then I guess I'll be returning it then doing it by upgrading which means I'll probably have to wait another month for another iphone5. And yes, I care that much about my highly sought after 310 area code...i'm very vain, j/k but seriously I want my old area code.