I currently have 2 lines with AT&T and want to open 2 new lines with Verizon and keep my current phone numbers. One of the lines is my mom's and she lives out of town. I want to get her a new phone and transfer her current phone number over but once I get the new phone I will have to mail it to her which could take 5 days. I don't want her to be without a phone until then. So if I open the new lines right now does it automatically de-active the phone from AT&T? Or can she keep using her phone until I get the new one to her?