Change sim, i want to keep my old phone number..?

how would i keep my old number to a different sim card? also if i do call the company is it possible to transfer all my previous contact numbers to my old sim aswell as pictures etc?Change sim, i want to keep my old phone number..?
if you buy a new phone, you are allowed to keep your old number even if you change providers. they have to allow you to do that. if you buy your phone from a reputable phone store like ATT or Verizon and not a big box store like Best Buy, they will be able to dock your old phone to your new one and transfer address books, pictures etc. Change sim, i want to keep my old phone number..?
i think it is possible to do that. all you are changing is your sim card not the service. unless you are going for new contract then you will not be able to keep your old number and the information from that.