Hello everyone! I am a new GM and am excited to use the SDC benefit. With a few well-planned SDC, I will easily hit PM by year's end; Not to mention having already paid the $50 change fee twice earlier this year. However, after reading Delta's rules I have a few questions. I've tried looking around the MilePoint and other boards, but cannot seem to find any comprehensive discussions. As I understand it, you can change to any flight on the same day, if that flight has seats available, 3 hours (firm guideline) prior to your new desired flight (not the old flight). So now here come the questions: Is SDC limited to the same calendar day, or is it a 24 hour period? If I was booked on a 6am flight, can I alternatively depart 8pm the night before, assuming the other conditions are met? Can I SDC to a different flight while in transit? For example, lets say I was traveling MCO-ATL-LAX. After completing MCO-ATL, can I then SDC to ATL-SLC-LAX? If yes, would having checked a bag change the answer to no? What about long layovers? If my first SDC flight is within the 3 hour window, but I want a connection 10 hours later, is that allowed? Does a second leg need to be within the 3 hour window, or a similar window? Can I SDC to a different flight after checking in online from home? I have tested the "change flight" option from the DL kiosks, and often see no available options displayed, yet ExpertFlyer.com does show some options. Am I better off always calling the medallion support line? Are there any other secrets that help with SDCs, or unforeseen hurdles? Other thoughts/comments? Thank you in advance!