Employee has 1day of balance and no negative balance but system is allowing to book multiple days?

Summary:

Hi Experts,

There is one employee he has one day of accrual balance and there is no negative balance allowed for this employee. here system shouldn't allow employee more than one day because he has only one day of balance but system is allowing to him to book multiple days

Content (required):

There is one employee he has one day of accrual balance and there is no negative balance allowed for this employee. here system shouldn't allow employee more than one day because he has only one day of balance but system is allowing to him to book multiple days