If the approved medical practitioner who carries out the medical examination required by section 38(2) of this Act is not satisfied—
(a)that the conditions mentioned in section 36(4)(a) and (b) and (5)(b) of this Act continue to be met in respect of the patient; or
(b)that it continues to be necessary for the detention in hospital of the patient to be authorised by the certificate,
the approved medical practitioner shall revoke the certificate.