5 CFR § 630.1207 - Notice of leave.
(a) If leave taken under § 630.1203(a) of this part is foreseeable based on an expected birth, placement for adoption or foster care, or planned medical treatment, the employee shall provide notice to the agency of his or her intention to take leave not less than 30 calendar days before the date the leave is to begin. If the date of birth or placement or planned medical treatment requires leave to begin within 30 calendar days, the employee shall provide such notice as is practicable.
(b) If leave taken under § 630.1203(a) (3) or (4) of this part is foreseeable based on planned medical treatment, the employee shall consult with the agency and make a reasonable effort to schedule medical treatment so as not to disrupt unduly the operations of the agency, subject to the approval of the health care provider. The agency may, for justifiable cause, request that an employee reschedule medical treatment, subject to the approval of the health care provider.
(d) If the need for leave is not foreseeable - e.g., a medical emergency or the unexpected availability of a child for adoption or foster care, and the employee cannot provide 30 calendar days' notice of his or her need for leave, the employee shall provide notice within a reasonable period of time appropriate to the circumstances involved. If necessary, notice may be given by an employee's personal representative (e.g., a family member or other responsible party). If the need for leave is not foreseeable and the employee is unable, due to circumstances beyond his or her control, to provide notice of his or her need for leave, the leave may not be delayed or denied.
(e) If the need for leave is foreseeable, and the employee fails to give 30 calendar days' notice with no reasonable excuse for the delay of notification, the agency may delay the taking of leave under § 630.1203(a) of this part until at least 30 calendar days after the date the employee provides notice of his or her need for family and medical leave.
(f) An agency may waive the notice requirements under paragraph (a) of this section and instead impose the agency's usual and customary policies or procedures for providing notification of leave. The agency's policies or procedures for providing notification of leave must not be more stringent than the requirements in this section. However, an agency may not deny an employee's entitlement to leave under § 630.1203(a) of this part if the employee fails to follow such agency policies or procedures.