Contact Starwood by email, sending attached a scanned copy of my Platinum card. Answer is bellow ( challenge)
Dear Mr. Meira,
Thank you for your status match inquiry. I am glad to be of assistance.
We do not offer a status match program, however, I do see that you are eligible for our Elite Status Challenges. In order to complete them, simply stay nine eligible nights for Gold, or 18 eligible nights for Platinum, within a three-month period you select, and your account will be upgraded within eight days of your last required eligible night. Only paid nights, booked at an eligible Starpoints-earning room rate, which posts to your SPG account, are valid toward this promotion. SPG Free Night Award and Cash & Points Award nights do not count toward this offer, nor do reservations booked through any third-party sources. During the month of March you may choose one of the following sets of months:
February 1, 2017 to April 30, 2017
March 1, 2017 to May 31, 2017
April 1, 2017 to June 30, 2017
Have a good day ahead . I look forward to hearing from you.
Starwood Hotels & Resorts Worldwide