How to restrict employees to enter absence for working day in a non working day Absence

Summary:

How to restrict employees to enter absence for working day in a non-working day Absence Plan.

Content (required):

How to restrict employees to enter absence for working day in a non-working day Absence plan. like for an example if a person working from Monday to Friday and his weekend is on (Sat and Sun) the person should only be able to enter absence for a non-working day (i;e Sat and Sun) that gets accrued into his absence balance. If person tries to enter absence for a weekday can he get a popup as not to enter time for a workday?