To take advantage of the right provided for in section 81.17.1, an employee must give to the employer advance written notice of not less than four weeks of the date on which the absence is to begin, the reason for it and its duration. However, the notice may be shorter for serious cause, in which case the employee must notify the employer as soon as possible.

The employee may return to work before the expected date after giving the employer written notice of not less than three weeks.