For changes "prior to departure", the rules for travel originating in Area 2/3 are a lot different than the rules for travel originating in Area 1. Since this discussion is about travel originating in CAI (Area 2/3), what you stated is incorrect according to the rules referenced below.

100N CHANGES
101N --------
102N .
103N PRIOR TO DEPARTURE
104N .
105N TRAVEL ORIGINATING AREA 1:
106N .
107N .
108N .
109N .
110N . BEFORE TICKETING DEADLINE:
111N .
112N . * PERMITTED WITHOUT PENALTY.
113N . * CHANGES TO THE FIRST INTERNATIONAL FLIGHT OR TO
114N . PRECEDING FLIGHTS REQUIRE TICKET REISSUE.
115N .
116N . AFTER TICKETING DEADLINE:
117N .
118N . * CHANGES TO THE FIRST INTERNATIONAL FLIGHT AND
119N . TO PRECEDING FLIGHTS ARE NOT PERMITTED.
120N . * DATE/TIME CHANGES TO OTHER FLIGHTS ARE
121N . PERMITTED AT NO CHARGE.
122N . * DATE/TIME AND ONEWORLD CARRIER CHANGES ARE
123N . PERMITTED WITHOUT REISSUE PROVIDED ORIGIN,
124N . DESTINATION, CONNECT POINTS AND INVENTORY REMAIN
125N . THE SAME.
126N . * CHANGES OTHER THAN DATE/TIME ARE PERMITTED AT A
127N . CHARGE OF USD 75.00. IF THE CURRENCY OF TICKET
128N . ORIGIN IS NOT USD, CONVERT THE USD AMOUNT AT THE
129N . BSR. THE TICKET MUST BE REISSUED.
130N . * CERTIFIED DEATH/ILLNESS OF THE PASSENGER, THE
131N . PASSENGER*S IMMEDIATE FAMILY OR AN ACCOMPANYING
132N . PASSENGER - REROUTING IS PERMITTED FREE.
133N TRAVEL ORIGINATING AREA 2/3:
134N .
135N . * UNLIMITED CHANGES PERMITTED WITHOUT CHARGE.
136N .