(a) An application for a certificate of appropriateness authorizing the relocation, demolition, or destruction of a designated landmark or a building, structure, or site within the district may not be denied, except as provided in subsection (c) of this section. However, the effective date of such a certificate may be delayed for a period of up to 365 days from the date of approval. The maximum period of delay authorized by this section shall be reduced by the preservation commission where it finds that the owner would suffer extreme hardship or be permanently deprived of all beneficial use of or return from such property by virtue of the delay. During such period, the preservation commission shall negotiate with the owner and with any other parties in an effort to find a means of preserving the building or site. If the preservation commission finds that a building or site within a district has no special significance or value toward maintaining the character of the district, it shall waive all or part of such period and authorize earlier demolition or removal. If the preservation commission or planning board has voted to recommend designation of a property as a landmark or designation of an area as a district, and final designation has not been made by the governing board, the demolition or destruction of any building, site, or structure located on the property of the proposed landmark or in the proposed district may be delayed by the preservation commission or planning board for a period of up to 180 days or until the governing board takes final action on the designation, whichever occurs first.