Thanks for query,
is a birth control pill usually taken for contraception
from first day of menstrual cycle
to 21 days.
You want to use this medicine for delay in your period right?
You take one pill daily from 7th August daily up to completion of your vacation i.e up to 20 th August.You will then get your withdrawal bleed about 24-27 of August.
If your regular period is between 3-9 August then it will not work though started from 7 th August.