Switching phone numbers

Hello,

I have two phone numbers - Number A which has the 40 dollar prepaid plan. I use this number with an iphone.

The second number is Number B it is with the 10 cent per minute plan. I use this with a regular cell phone.

All I want is the switch the phone numbers so my iphone gets the Number A with the 40 dollar prepaid plan.

Is this possible and how to do that? thanks!