
The first photo shows you the ComfortFlex i button in the circle. When you hover over it it gives you the dropdown box in the second photo.
I'm not trying to get a cheaper fare. I am trying to change the time of the flight on the same day in the same category that I bought ages ago. There are 10 flights (just with Aegean) from JTR > ATH each day. I assume they aren't all full.