18. (1) Subject to subsection (2), a donor under section 14 or 16 of an embryo may, by notice in writing to the operator of the DAHR facility to which his or her declaration under section 14(5)(b) or section 16(5)(b), as the case may be, was made, revoke his or her consent under the relevant section.

(2) A revocation of consent under subsection (1) shall have no effect in respect of a DAHR procedure or, as the case may be, a further DAHR procedure to which the consent relates that has been performed before the notice under that subsection is received by the operator of the DAHR facility at which the procedure is performed.