1. Whenever a claim under sections two hundred sixteen or two hundred seventeen of this article is disapproved or disallowed, in whole or in part, the chief of staff shall cause notice thereof to be served by mail upon the claimant or his attorney. Within six months after the service of such notice the claimant may apply to the chief of staff for a rehearing of his claim. The chief of staff may deny or grant such an application. If granted, the chief of staff may appoint, as appropriate, another medical examiner or board as provided by section two hundred sixteen of this chapter or another pension examining board as provided by section two hundred seventeen of this chapter.2. The provisions of subdivision three of section two hundred sixteen and of subdivisions two, three and four of section two hundred eighteen of this chapter shall be applicable with respect to claims reheard pursuant of this section.