If you call Shotgun verbally and then go back inside, or back to where the deed took place for some reason, you must re-call Shotgun after leaving the building.
Be sure to check for your wallet, keys, ID, shoes, backpack, tablets, computers, cell phone, snacks, etc before heading out the door to call shotgun.
2.2.1 After the original Shotgunner has re-entered the building or returned to where the deed took place, Shotgun is once again fair game to all other passengers.
2.2.2 The second person to call Shotgun does not get Shotgun automatically. They too must recall shotgun, once the original Shotgunner has reentered the building or returned to where the deed took place.