+1 Thanks. I also found this post on the subject.
1.) The ported number must be in the same rate center that you reside in. In other words, if you are moving from one location to another, the phone number must be within the same rate center in order to be ported over. If the phone number crosses rate centers, the port cannot take place
2.) The customer's name must match exactly what is on their account with the other provider.
3.) Customers must keep the telephone number active with the other service provider, in order for the port to be successful. The telephone service is then canceled through the other provider once the port completes.