Emailed GHA Discovery firstname.lastname@example.org
but never got a reply to status match from my Hilton Honors Diamond to their GHA Discovery Black tier so I called their USA toll free number and spoke to their agent. She said that they will only match 1 tier up from what you currently hold. So if you are only a Gold member they will only match you to Platinum but you need to provide proof of an overnight stay with one of their properties.
They require 10 nights to go from Gold to Platinum and with their DOUBLE NIGHTS promo that means if you stay at one of their participating properties you can obtain Platinum status with 5 stays instead of 10. They will then be able to match you up to Black status with screenshot proof of your last stay.