If you're saying that you want to have the same number on that phone, as on a phone that you're using already, as far as I know that cannot normally be done (though I recall a member in the Netherlands saying that it is possible there). But seek advice from your carrier or network provider.
If you simply want to use your old phone alone, with your present number in it, just put the SIM from your present phone into the old phone.
Posted via the Android Central App