If I remember correctly, the first time I bought Ambassador status I was automatically upgraded to Platinum, but had to earn Platinum when I renew my Ambassador the following year.

Here's what it's says on the Intercontinental site under Ambassador benefits:

http://www.ichotelsgroup.com/interco...fits/lm/reward

REWARD
Being an InterContinental Ambassador also means you are automatically an elite Priority ClubŪ Rewards member - allowing you to earn points and redeem for rewards with the wider Priority Club Rewards Family of Brands

I think "elite" equals Platinum.