Probation for exempt employee

Does anyone know if "probation period" is legal for exempt employees. Available sick/vacation days are not available for 90 days - employee wants to take 1/2 day for personal business. Their available days are not activated until after probation. Can the employee be docked for missing 1/2 day?
Comments
Probation period is usually in order to withhold benefits for exempts or review their performance.
You cannot dock their pay even if probationary period unless full day absence.