You still have me confused about the reasoning to swap numbers. If your virtual number is not currently an independent line on port 2, then swapping the numbers doesn't accomplish anything. Whether you apply the BYOD credentials now (or after the swap) to your SIP phone now, all incoming calls from both DID's will ring your SIP phone and any other phones you have hooked to your ATA. The only reason that I can see to swap numbers is if you plan to convert your current main number to a 2nd line after it's been swapped to a virtual number.