Port number from one Telus Epp to another

You can't port between 2 Telus postpaid accounts, but you can do as you suggest and port to a prepaid account. My experience of porting between any of the Telus family of mobility services was the port was nearly instant. I'm uncertain how quickly you can port again, but worst case, you would need to use the prepaid account for a few days or week(s) to port back.