From IHG Rewards Club Platinum Elite
To Best Western Rewards Diamond

Matched via the status match form on the Best Western website (www.bestwestern.com/en_US/best-western-rewards/status-match.html). I have Platinum Elite courtesy of the Ambassador programme at IHG. Filled in the form with my Best Western membership #, name, and status with IHG and within two hours received an email from them confirming my upgrade to Diamond.