score:-1
Short answer: PAX=passenger, and the ticket says "passenger" there because the entire line "PAX /C1-4 NON END/CHNG PENALTIES AS PER RULE" was copied from the Amadeus program (which mentions PAX
).
Looking at the Amadeus training manual (Jan. 2012), the PAX line comes from Amadeus:
and PAX means passenger:
Additionally, Locutus_WPC mentioned on Reddit:
In this context PAX probably refers to an adult passenger. Would’ve said CHD or INF if describing a child or infant fare.