Join Date: Aug 2002
Location: WAS/TYO
Programs: UA 1K, AA EXP (3MM), DL PM, BONVOY TITANIUM, HYATT GLOBALIST, HILTON DIAMOND, IHG DIAMOND AMB, et al
Posts: 6,234
Vouchers can be used for the purchase of 500-mile upgrades. I used to do that with most of my vouchers back when I was a PLT. Everytime I did it with the help of an AC agent. The one downside, however, is if your voucher doesn't exactly fall on a multiple of the sticker price, you cannot co-pay the difference to the next sticker.
-FlyerBeek