Vacation Rule - How to ignore the start and end time and use only the date or is there an API to upd

Hello,

We have issues where our users are forgetting to put the correct start and end times when the vacation rule is created. As a result they end up creating a rule which starts after they ahve left the office and they continue to receive transactions which they thought should have been going to the person to whom it is delegated / transferred.

My questions is:

a. Is there a way to have the workflow look at only the date and not the start and end time without too much customization.

b. Is there an API which can read the date and enter the start time as 00:00:00 and end time as 23:59:59.