Originally Posted by
fumje
Assuming all those flight numbers are SFO-EWR, yes, that's correct. You can make progressive changes, subject to inventory availability. If you have a discount economy fare though, around S / T or below, don't expect inventory to be open.
I get it, but it's worth a shot, right? If it's free, then why not? I know SFO-EWR flights can get full quickly.