If any nonconforming use of land, structure or portion of a structure ceases use or operation for a period of six months or more, and the owner within a total period of 12 months from cessation fails or refuses to apply to the Zoning Officer for a permit to reinstitute or continue the original use, or fails to immediately, actively and consistently market the availability for reuse (such as newspaper ads, premises' signs with corresponding newspaper advertisements, and listing or marketing agreements), then the failure or refusal shall be conclusively deemed to be an abandonment of the original use. Any subsequent use of the land, structure or portion of structure shall conform to the requirements of this chapter in the district in which it is located. From the time of such application to reinstitute or continue the use, the owner shall have not more than one year to reestablish the use. In the case of an owner diligently attempting to secure a viable new tenant or buyer, the period shall be extended to two years whereby the owner must reestablish a nonconforming use of an equal or more restrictive (milder) classification. Simply placing a sign or signs on the premises shall not be considered as due diligence in maintaining or reestablishing nonconforming status.