[Resolved]  Indigo Airlines — allotment of seat near emergency exit

Sir,
I have traveled on 21/3/2018 by flight no. 6e 407 from pune to bengaluru with seat no 13a & by flight no. 6e 902 from bengaluru to mangalore with seat no 13f, both seats were near emergency exit, however while coming back on 25/3/2018, even i was having boarding pass for flight no 6e 178 and 6 e 476, for mangalore to bengaluru and bengaluru to pune with seats near emergency exit, but at airport the seats were were changed with reason that the age is more than 60 years and that seat was allotted to a lady with same age for flight no 178.
Request to explain the exact rules for emergency exit seat allocation.
Patil v b