My experience today seems to confirm that *G get SDC for free, but nobody at UA seems to understand the details. I also have an example of how not to do an SDC for Star Gold flyers.

Last night I logged on to my no status MileagePlus account and then brought up the record for an SDC. Both my wife and I are A3 *G. The website priced the change at $75 each, but failed after I entered a credit card number. After 2 failures I was offered a call back. He asked me what price the web quoted. I said $75 and he told me he would get the charge in for $75 each and that the flight change was already done.

At the airport this morning it took the agent 30 minutes. He made 2 calls to support and finally gave up. The ticket online shows the changed flight and no extra charges over the base fare. My credit card shows temporary authorizations of $150 last night and $150 4 times today. My guess (and hope) is none of these charges will "stick" since there are no extra charges reflected in the reservation.

My advice is for *G flyers is not to log in before attempting an SDC.