As a guest, not as a performer. Invited but turns down the invite still resolves to YES. Close date updated to 2023-12-01 12:00 am. Resolves Jan. 1st.

2023/10/09 EDIT: Invite has to be from someone who can credibly offer 'if you come you'll be welcome', which in practice means the organizing team, probably the primary organizers but possibly the choir director or similar.