When you were younger, a change of plans could throw you into tears or tantrums. For a young child, a change of plans often takes the same course as disappointment. As you recall, we are usually disappointed because our expectations are not met.
A change of plans falls into a slightly different category, however, because you are not throwing out your intentions altogether, just selecting different ones.
That said, a change of plans can challenge most anyone's flexibility and adaptability. That's because a change of plans brings with it some uncertainty. A change of plans may not always bring favorable circumstances. On the other hand, a change of plans will sometimes create better opportunities or events.
A large part of whether a change of plans works for you is your own willingness to move ahead without interjecting the static of your own disappointment, frustration, evaluation, or comparison.
There's more, but for now, try lowering the volume on your own personal commentary when you encounter a change of plans. I think you'll be pleasantly surprised what may happen next!