Double-checking a few more things:
a) in general, it's best to have two OWs instead of one RT to maintain maximum flexibility. However, if I end up having to cancel both OWs, will I then have to pay $300?
b) if I have a RT, is it possible to push the outbound past the return (i.e. switch the first flight from PHL-TLV to TLV-PHL), and if so is that considered a change in origin/destination?
TIA!