A referral certificate ceases to have effect if:
(a) it is not accepted by a lawyer within 28 days after the referral; or
(b) a Pro Bono lawyer has provided the legal assistance mentioned in the referral certificate; or
(c) a Pro Bono lawyer has ceased to provide legal assistance under rule 4.15; or
(d) the proceeding to which the referral certificate relates is finalised or transferred to another court.