Whether responding to a wedding, dinner or formal invitation, it is essential that you understand proper etiquette in replying to the offer. When someone extends an invitation to an event, it is important to remember that as much as she is hoping that you will be able to attend, she is equally as interested in being told whether you are not going to attend. Much centres on guest count, so do not keep your hosts waiting and provide a speedy reply to an invitation in an appropriate fashion.
First and foremost, decide whether you will be able to attend the event. A good host will send out invitations in enough time to allow you to possibly adjust your schedule so that you might be able to attend. It is important to look over all prior commitments and make a definitive decision. One of the most frowned-upon responses to an invitation is a conditional response of "I might" or "I could attend if." This will certainly not help your host in planning the event and can make you look relatively insensitive to her hard work.
If you can attend the event, provide essential information. If you find that you are absolutely able to attend, barring any unforeseen emergencies or extenuating circumstances, then make sure to fill out and send the response card. Depending on the type of event, whether more formal or informal, the host may provide a response card that asks for such information as number of attendees and meal preferences. Be sure to answer all of the host's questions with as specific and accurate information as possible.
If you cannot attend, express your gratitude. Things come up, conflicts happen, but regardless you should still express to your gratitude for the invitation. Even though you will not be attending the event, it is still important to respond to the host as quickly as possible. Tell him how grateful you are for the invitation and how you wish you could attend but prior engagements prevent you from doing so.
Enclose a note for a written RSVP. While many hosts are opting to do RSVPs online or over the phone, for those who still ask for a written confirmation of attendance it can be a nice addition to include a short note as well. Whether you can attend or not, you can use the note as a way to express your excitement over the event if you are going or send best wishes to the event's host if you are unable to attend. These notes should be short and to the point, and be written in the style of the invitation you received.
Send the RSVP. Be mindful of how the RSVP should be received. Some prefer that word be relayed over the phone or via e-mail, so make sure that your RSVP follows suit. It is also important that the information be sent to the appropriate address.
It is important to respond to an invitation as quickly as possible. For many events, the host is anxiously awaiting your response in order to plan meals and seating arrangements, so it's important to let him know if you will be in attendance as soon as you know whether you can go.