A friend has organised a birthday party for her dad. She has a small family and he has few friends so she has invited all of her friends. She really wants everybody to go and is the type to take it personally if you don't go. Her dad is lovely and does deserve a good night. However I've also received an invitation to a hen do on the same evening. I'd much rather go to the hen do as that's for my friend whereas the party is my friends dad. I've already accepted and confirmed the part invitation before the hen do invitation arrived. WIBU to now decline the party invitations? WWYD in this situation?