; (B) notify the employee that this written statement may be modified in writing at any time during employment; and (C) specify the process to modify the written statement. (b) Offer of desired weekly work hours to existing employees (1) In general Except as provided in paragraph (2), an employer shall schedule an employee of the employer to work the number of weekly hours identified by the employee as desired weekly hours in a written statement under subsection (a) prior to hiring any new employee from an external applicant pool, including hiring through the use of a temporary services or staffing agency, or contracting with a contractor or subcontractor, to work such hours. (2) Exceptions An employer may hire an individual as a new employee, or engage a contractor or subcontractor, to perform work for the employer if— (A) the employer needs to fill hours for which no employees of the employer who have provided written statements under subsection (a) are available based on such written statements; (B) all employees of the employer who have provided written statements under subsection (a) lack, and cannot obtain with reasonable training, the qualifications necessary to perform the work