Your dear friend from college is hosting her first dinner party, but unfortunately, it's on the same night you're going to meet your boyfriend's parents. You hate to hurt her feelings, but you simply have to decline. If you do so promptly, expressing your regrets and thankfulness for her friendship, there should be no hard feelings.
Rejecting a Written Invitation
Let the person know as soon as possible that you won't be able to attend the event. This allows her to provide accurate information to the caterer and attend to other details that are dependent on the number of people who attend.
Use the RSVP card that came with the invitation to send your regrets. If there is no response card, write a response and send it to the address on the envelope, note etiquette experts at EmilyPost.com. If the invitation indicates that you should respond by phone, call the phone number and ask to speak directly with the host.
Let the host know why you won't be attending. You needn't provide a lengthy explanation -- a simple "I'm sorry, but I have a prior commitment that evening" will do.
Thank the host for having thought to include you in their festivities. Let her know you were delighted to have received the invitation and that you look forward to seeing her on another occasion.
Rejecting a Verbal Invitation
Just say no. William Ury, author of "The Power of a Positive No," notes in an interview for Oprah.com that a "quick 'no' is better than a slow 'maybe'." You don't have to be blunt, but saying, "I won't be able to go with you to the art opening tonight. I need to spend some time with my husband," is clear and polite.
Apologize for not being able to attend this time, and let the person know that you enjoy their company. You could say something like, "I'm sorry to miss it, though. I really enjoying spending time with you."
Thank her for inviting you. Say, "You're always so thoughtful. I appreciate you making room for me in your plans."
Follow up with the person later and ask her how the event went. Let her know that you wish you could have attended. Showing an interest in someone's life can help to get rid of any sting of rejection she might have felt when you declined her invitation.