This is a classic excuse that is always believable. You could say that a close family member has fallen ill or had an accident, and that you need to be with them.
2. Work Commitment
If you have a job that requires you to travel or work overtime, you can use this as an excuse for missing a party. Just say that you have a last-minute project that you need to finish, or that you have to attend a work conference.
3. Illness
If you're feeling sick, you can use that as an excuse for missing a party. Just say that you don't want to spread your germs to anyone else.
4. Transportation Issues
If you don't have access to transportation, you can use that as an excuse for missing a party. Just say that your car broke down or that you missed your train.
5. Previous Engagement
If you have another commitment that you can't get out of, you can use that as an excuse for missing a party. Just say that you already made plans for that time.
6. Personal Reasons
If you don't want to attend a party for any other reason, you can simply say that you have personal reasons for not being able to attend. You don't have to give any details if you don't want to.
It's important to be polite when you're declining an invitation to a party. Be sure to thank the person for inviting you, and let them know that you're sorry you can't attend. You can also offer to reschedule if possible.