In addition to a user updating their own RSVP, Administrators, meeting Collaborators and Group Owners can update RSVP's in the Meeting Center. 


To update the RSVP for a user go to the People section of the meeting.



Go to the RSVP section, and select the rsvp you would like to update, select one of the options:


Once you select the new RSVP it will be automatically saved.