(a) An employee may use disabled veteran leave only for the medical treatment of a qualifying service-connected disability. The medical treatment may include a period of rest, but only if such period of rest is specifically ordered by the health care provider as part of a prescribed course of treatment for the qualifying service-connected disability.

(b)

(1) An employee must file an application—written, oral, or electronic, as required by the agency—to use disabled veteran leave. The application must include a personal self-certification by the employee that the requested leave will be (or was) used for purposes of being furnished medical treatment for a qualifying service-connected disability. The application must also include the specific days and hours of absence required for the treatment. The application must be submitted within such time limits as the agency may require.

(2) An employee must request approval to use disabled veteran leave in advance unless the need for leave is critical and not foreseeable—e.g., due to a medical emergency or the unexpected availability of an appointment for surgery or other critical treatment. The employee must provide notice within a reasonable period of time appropriate to the circumstances involved. If the agency determines that the need for leave is critical and not foreseeable and that the employee is unable to provide advance notice of his or her need for leave, the leave may not be delayed or denied.

(c)

(1) When an employee did not provide the agency with certification of a qualifying service-connected disability before having a period of absence for treatment of such disability, the employee is entitled to substitute approved disabled veteran leave retroactively for such period of absence (excluding periods of suspension or absence without leave (AWOL), but including leave without pay, sick leave, annual leave, compensatory time off, or other paid time off) in the 12-month eligibility period. Such retroactive substitution cancels the use of the original leave or paid time off and requires appropriate adjustments. In the case of retroactive substitution for a period when an employee used advanced annual leave or advanced sick leave, the adjustment is a liquidation of the leave indebtedness covered by the substitution.

(2) An agency may require an employee to submit the medical certification described in §630.1307(a) before approving such retroactive substitution.