The former parent, at any time more than 12 months after the making of the order under section 18 when—
may apply to the court which made the order for a further order revoking it on the ground that he wishes to resume the parental rights and duties.
While the application is pending the adoption agency having the parental rights and duties shall not place the child for adoption without the leave of the court.
Where an order freeing a child for adoption is revoked under this section—
but the revocation does not affect any right or duty so far as it relates to any period before the date of the revocation.
Subject to subsection (5), if the application is dismissed on the ground that to allow it would contravene the principle embodied in section 6—
Subsection (4)(a) shall not apply where the court which dismissed the application gives leave to the former parent to make a further application under subsection (1), but such leave shall not be given unless it appears to the court that because of a change in circumstances or for any other reason it is proper to allow the application to be made.