Hi, my wife is due an upgrade, my son is going to take it and she will continue on his phone

[Kathy21]

How do I switch phone number mid contract, my wife will continue my sons contract but needs to move her number and he needs to port his number to the new contract, thanks 

[PandJ2020]

If you are keeping a phone then it's not an update (swap).  You simply purchase a new phone.

You cannot port numbers within a network.  You simply put the associated SIM in the appropriate phone.