I made the call, and the representative told me that she made the change on my account. Any idea how long it takes for the change to reflect online? When I check online, it still shows me on the "15 stays" plan.

It won't reflect online. At the end of the promotion, someone will go in and manually update your point balance to reflect the promotion to which you were switched.

Remember to double check that someone actualy does the update. Last year I had to write in and remind them.

For those that were interested in the double nights promo - even as platinum you can't change into that one. There was even one out there for double nights and points, I think we all would have gone for that one if they let us. (No, you can't change to that one either). For more details you can look at this thread:
http://www.flyertalk.com/forum/showt...highlight=mega