Skip acouple feeding to get it more hungry. Let time be on your side. It may take a long while but don't give up and eventually the snake will take the other food. Remeber snakes can go months without eatting so it can take a while, but they won't starve themselves to death. If you don't wait it out and give them a mouse thinking you can try again later, that jsut shows them that if they wait long enough they will jsut get what they want. Sometimes snakes will santchup a new prey pretty quick. I have had that happen a few times but I have also had to wait over 2 months before they would take the new prey a few times as well.