You have to first prerecord a video of you talking to your dog, then do the blanket trick where you stand in a doorway and lift a blanket blocking line of sight betweennyoy and the dog. Play the video you made earlier and put it by your feet, then stand outside of the door frame, drop the blanket, and run outside/jump out a window.
The dog will think you're either really good or totally shite at magic(depending on their opinion of you) and that you trapped yourself in a phone. Now when you call them they will think its the real you.
When you get back do the trick in reverse!