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Resolution 735.
PERIOD OF VALIDITY.
RESOLVED that, unless otherwise specifically provided in the applicable fares resolutions:
1. The period of validity for tickets issued at one way, round or circle trip fares shall be one year from the date of commencement of travel, or, if the first flight coupon is open-dated, and/or unused from the date of issue thereof.
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4. Travel under each flight coupon whether related to a normal or special fare, must be scheduled to commence before midnight, local time at the airport of departure, of the date of expiry shown on such flight coupon.
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6. Definitions.
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6.2 “MONTH(S)” for the purpose of determining duration of ticket validity, shall mean a period of time from a given date in one month to the corresponding date in a subsequent month, e.g.:
one month validity 01 January–01 February;
two month validity 15 January–15 March;
three month validity 30 January–30 April.
Exception 1: Where the corresponding date does not exist in a shorter subsequent month, then the month(s) shall mean from a given date in one month to the last day of such shorter subsequent month, e.g. one month validity 30 January–28/29 February.
Exception 2: When the “Given Date” is the last day in one month, then the “Corresponding Date” in a subsequent month will be the last day in such subsequent months, e.g.:
one month validity 31 January–28/29 February;
two month validity 28/29 February–30 April;
three month validity 30 April–31 July.
6.3 “YEAR”, for the purpose of determining the duration of ticket validity, shall mean a period of time from the date of ticket issue or the date of commencement of travel, as applicable, to the corresponding date in the subsequent year, e.g.:
one year validity 01 January 89–01 January 90; 28 February 89–28 February 90; 29 February 00–28 February 01.
I hope this can now answer all questions.