sleep on it, if you are very excited or upset, take some time to calm down
i just had to cancel to an reservation, no refund and no expectation of one. my would-be host immediately sent a rude message before i had the chance to apologize and explain. they then sent a a very polite message, but the damage was done. if you are upset or excited step away from situation for a moment. if you can, sleep on it. you might stop yourself from doing something you regret, like being mean or committing to something you can't really handle.