Compromise is a basic negotiation process in which both parties give up something that they want in order to get something else they want more. Compromises usually occur in win-lose situations -- when there is a fixed pie to be divided up, and whatever one side gets, the other side loses.
Compromise and arrangement refer to a legal process under which a company can restructure its debt or equity capital, or both, in a manner that is acceptable to its shareholders and creditors.
A petition to set aside an order approving compromise and release is, in effect, a petition to reopen. It requires a showing of good cause. It is not uncommon that one party alleges "mutual mistake," while the other party asserts the mistake was unilateral. This is ultimately decided by the trier of fact.