The
fares, charges or rules applicable to any transportation shall be those
in effect at the time of commencement of transportation (i.e. use of
the first flight coupon of a ticket or conjunction ticket for carriage).
Once carriage has commenced, any change in fares, charges or rules does
not affect the contract and may be disregarded, unless otherwise specifically
provided. In case of any change (including changes due to an altered
conversion rate) in fares, or new rules, effective between the day the
ticket is issued and the day of commencement of travel, the passenger
is required to pay the difference in the fare or he will be refunded
such difference, as the case may be.