Where changing is necessary

One situation to where chaning palns becomes nesscessary is when  you plan to go one trip and your friends plan to go to universial studios. You plan out what your going to buy, wear, and what rides your going to get on. You plan it a week before friday after school. You and some friends plan to take the bus to universial studios and to get picked up from your parents to stay at the theme park more longer. So after school you and a bunch of friends ride the bus to universial studios, when you get there you do everything as planned until in the middle of the trip, your mother calls and says that you have to leave early because the car broke down so they can't come get you. Your furious because now you have to leave early and take the bus home. So you tell your friends and they leave with you. When you get home you guys talk and plan another day but hopefully this time you pray that your plans work out.