How does one trace a new cell phone number from an old one?

What do you mean by trace ?

Know where it is, know who has it ?

By saving the numbers (if you can) into the sim card.. But this will only work if you will use the same sim card on your new phone

My brother has a company phone of browns implement in floydada,Texas number 806-983-4774 it was changed yesterday its with verizon how can I find new number?