How Can A Period Be Postponed?

Hello doc, i am 24 yrs old. In the month of dec i had my periods on the 24th of dec but in jan i had it on the 16th usually my periods are in the cycle if 28 to 30 days. But this month i have prior committments to travel from 15th to 22nd and would like to delay my periods after 22nd. Kindly help thanks