I was told by Marriott representative, that the stay has to occur within 6 months, so you would have to have a reservation before November. I don't think, they would renew it, but you could always try. I also don't think you could get your annual fee back from this year's renewal, as it's been too long since May. But you could always cancel it before the next renewal. That should not affect your current certificate. Yes, the 6 months expiration is a huge drawback of this scheme and one of the reasons I canceled my Marriott visa.