The WORKDAY function syntax has the following arguments:
Start_date Required. A date that represents the start date.
Days Required. The number of nonweekend and nonholiday days before or after start_date. A positive value for days yields a future date; a negative value yields a past date.
Holidays Optional. An optional list of one or more dates to exclude from the working calendar, such as state and federal holidays and floating holidays. The list can be either a range of cells that contain the dates or an array constant of the serial numbers that represent the dates.