Originally Posted by
docbert
A few seconds on their website would have found you
https://www.united.com/web/en-US/con...daychange.aspx, and specifically :
You may stand by if seats are not available in the purchased fare class. In these cases, the same-day change fee will apply, but will not be charged unless you are assigned a seat on your alternate flight.
Interesting that this is in conflict with what the check-in agent told the OP per his first post in this thread. The OP claimed that he was told he would have to pay the SDC fee just to get on the stand-by list. Your quote (from United's web site) says clearly that the SDC fee "will not be charged unless you are assigned a seat on your alternate flight."
So the confusion appears to be with the check-in agents that told the OP that the SDC fee would have to be paid just to get on the stand-by list.