Thank you for the invitation.
I am pleased to RSVP and will attend.
Thank you for the invitation, but I regret that I cannot attend.
Please consider this my RSVP for the event.
I look forward to attending.
Unfortunately, I am unable to attend.
I would be happy to join you.
I appreciate the invitation and will be there.
I’m sorry I cannot make it.
Kindly confirm my attendance.