Originally Posted by
starflyer
As per a strict reading of the posted T&Cs (link:
http://www.delta.com/traveling_check...erms/index.jsp), it appears that the Same-day Standby option is available to you as long as you are only doing a stand-by for the domestic portion of your travel, and both you and your traveling companion are DM, PM, or GM. I no longer fly Delta, so I can't say whether practice matches posted T&Cs.
While this could be worded better, a strict reading of the t&c would not permit this because OP holds an ATL-FRA itinerary which happens to stop at JFK. If he purchased ATL-JFK and JFK-FRA (which would likely be a lot more) he would be able to SDC/SDS on the first segment.
OP's best bet is to call DL, say that he got the message and simply propose that DL switch him to the earlier ATL-JFK flight. I would not get into the complexities of DL's rules. Let the CSR deal with the issue and s/he might just do that.
I would not rely on same-day anything because those flights are often oversold so the fee is the least of the issues. OP needs to be at JFK at least 2 if not 2:30 pre-departure for FRA.