Can you port a cell phone number to an existing account with a diff carrier?

[azhoopsfan]

I'm under contract with ATT but interested in moving to Verizon and want to get in on the grandfathered unlimited data plans that expire on 7/7.  I have an old Verizon phone that I can activiate on a month-to-month plan until a better 4G LTE phone I like comes out. 

My question is this:  Can I activate the old Verizon phone on a cheap month-to-month contract with unlimited data and get a new phone number and then (at a later date when the 4G phone I want comes out) cancel my ATT phone and port my ATT number to my Verizon phone?  Or will the fact that the Verizon account is already set up with its own phone number prevent porting my number? 

Thanks

[AsherO]

I'm under contract with ATT but interested in moving to Verizon and want to get in on the grandfathered unlimited data plans that expire on 7/7.  I have an old Verizon phone that I can activiate on a month-to-month plan until a better 4G LTE phone I like comes out. 

My question is this:  Can I activate the old Verizon phone on a cheap month-to-month contract with unlimited data and get a new phone number and then (at a later date when the 4G phone I want comes out) cancel my ATT phone and port my ATT number to my Verizon phone?  Or will the fact that the Verizon account is already set up with its own phone number prevent porting my number? 

Thanks

I'd say it depends on the rules of the carrier you're porting to. You can definitely port to add a line to a family plan, and the like, but there are no guarantees they will offer a grandfathered rate to the newly ported number.