RSVP stands for répondez s'il vous plaît, which is French for please respond. It is important to respond to any invitation, but especially one with an RSVP so that the host knows how many people to cater for. Here are some tips:

• Never ask a host who else is coming;
• It is impolite to change your mind after you have responded, even if a better offer comes up;
• Respond earlier rather than later;
• Formal invitations to weddings sometimes have an RSVP card that you can complete and post back;
• Often the host will let you know how they want you to respond by leaving their email address or phone number;
• It's rude to ask if you can bring someone unless the invitation specifies 'and guest' or 'and partner.'