The reserve price can be lowered to meet the high bidder's bid. At least in the past I have seen this happen where a bid at a certain price did not meet the reserve and the seller lowered the price so the same bidder was the high bidder without rebidding with the reserve met at the same price. This was back in the days when all the bids with the identities were shown so it was easy to see if someone had rebid and if it was the same individual. In either event if someone place a token bid on something thinking they are not obligated, the reserve can always be lowered to execute their bid in which case then they are obligated theoretically.
You cannot raise the price though once a bid has been placed. Maybe that is what you are thinking of in terms of no changes. However, I have not followed this for a while so I do not know if the rules have changed.
I've found the link which describes "Lowering Reserve Prices".
http://pages.ebay.ca/help/sell/lowering-reserve.htmlIt states:
You may lower the reserve price on an item in any category as many times as you like, as long as the reserve price has not been met and there are at least 12 hours left on the listing. When a reserve price has been lowered, all bidders are automatically notified by email.
If you lower the reserve below the high bidder's maximum bid, the high bidder's maximum bid will be lowered to $1.00 below the new reserve price. The new reserve price will be revealed to the high bidder by email. This lets high bidders confirm they are still interested in the item.When you lower the reserve price eBay lowers the maximum (proxy) bid. When the maximum bid is lowered:
A bidder must bid again to meet the new reserve price.
eBay lowers the maximum (proxy) bid 1.00 below the new reserve price.
A bidder must bid again to confirm interest in the item because the high bidder may have bid on another item when that bidder did not initially meet the reserve price.
The high bidder is not bound to purchase the item; the high bidder must either bid again at or above the new reserve price.
(in any event, my buddy would have never have won the item, because had the seller lowered the reserve price to $5,000, my buddy's bid would be automatically changed by eBAy to $4,999 (still below the reserve price).