FlyerTalk Evangelist and Ambassador: The British Airways Club
Join Date: Jun 2008
Location: Somewhere between 0 and 13,000 metres high
Programs: AF/KL Life Plat, BA GGL+GfL, ALL Diam, Hilton Diam, Marriott Gold, blablablah, etc
Posts: 33,193
Just answering my own question - not sure if it would differ at the airport (won’t try) but at least on the app, the earlier flight no-fare-difference option is not offered for same day change to earlier flight and instead the full fare difference is asked.