To give a more serious answer, as others have mentioned, in a case like this, it's best to look at things in reverse. Our daughter a couple of years ago was offered and accepted a position 1,000+ miles away. She had already resigned the job she had, given up her housing, had packed up all her belongings, and had scheduled a moving company to transport her stuff. She had agreed to a rental in her new city and put down deposit money. The day she was supposed to head out, the company notified her they were going in a different direction and her services were no longer needed. When she explained all that to them, they essentially told her too bad, so sad. She was able to get her deposit money back and put her stuff in storage instead. She ended getting a much better job for way more money someplace else, so things worked out in the end. Bottom line, I wouldn't feel that bad about turning down a position you already accepted. Companied rescind offers after the fact pretty often, it's not the end of the world.
I think she may have had legal recourse to recover some damages if she was intent on pursuing it.
Here’s an excerpt from a publication discussing PA law:
The Supreme Court of Pennsylvania articulated the necessary elements for a claim of promissory estoppel as requiring:
(1) the promisor made a promise that he should have reasonably expected would induce action or forbearance on the part of the promisee; (2) the promisee actually took action or refrained from taking action in reliance on the promise; and (3) injustice can be avoided only by enforcing the promise.
Damages in a Detrimental Reliance Dispute
In detrimental reliance lawsuits, plaintiffs are generally limited to “reliance” damages, i.e., those losses directly suffered by the plaintiff as a result of their reliance. The damages are designed to restore the injured party to the economic position occupied before the party acted in reasonable reliance on the promise.