IHG One Rewards offers Confirmable Suite Upgrades after 20, 40, and 70 nights in each calendar year, and each certificate can be used for up to five nights. However, because many prepaid rates and all award night redemptions have not been eligible, these certificates have had limited usefulness. According to Loyalty Lobby, suite upgrade certificates may soon be usable on points stays or free night certificates as well.
UPDATE: It appears that IHG is unclear whether these can be applied for awards night or not. The Ambassador Service Center told me that the functionality came online on May 31 (I had previously heard it would come on June 1) . I will try to confirm this with the IHG and will do an update.
After looking through the comments, it seems that no one has successfully done this yet, and customer service has given mixed answers. However, after checking the terms for suite upgrade certificates, I did notice some signs that changes may be coming. The wording below is still a bit unclear: does it mean suite upgrade certificates will be usable on the Ambassador complimentary free night in the future, or on all award bookings? We’ll have to wait and see.
Reward Night/Free Night, including Ambassador Complimentary Weekend Night (eligible at a future date)
How IHG suite upgrade certificates work
1. When to apply: from 14 days before check-in until 24 hours before check-in
2. Stay length: eligible for stays of up to five nights
3. Restrictions: prepaid rates are not eligible; currently award nights and Free Night bookings are also not eligible
4. How to apply: cannot be requested online; you must call IHG One Rewards customer service or the Ambassador Service Center
5. Suite types: in most cases, you can choose from multiple room types and suites.