I'm due to renew my Ambassador membership early next year, and I plan to use a weekend night at Intercontinental Singapore on a vacation I have planned and booked for June 2024. When I was speaking to the consultant at IHG Diamond bookings, they said they can book the 5 nights at IC Singapore as flexible, and then when I renew Ambassador I can change it to a non refundable booking.  This sounded a little too good to be true, has anyone else tried this?  The weekend night is confirmed this way, and its flexible until I renew next year.
I wonder what the latest date is that I can change an early June booking to non-flexible to save $...  Also at that time, can I use points for reward nights?  Noting that my Diamond status expires Dec 2024, and I think the Ambassador membership expires around March 2024.
Does anyone have any other advice?