Expiration of approval. Conditional use or use by special exception approval shall expire automatically without written notice to the applicant if, within 12 months of said approval, no application for a grading permit or building permit is submitted to undertake the construction or no certificate of occupancy is obtained to authorize the occupancy described in the application for conditional use or use by special exception approval, unless Borough Council or the Zoning Hearing Board, as the case may be, in its sole discretion, extends conditional use or use by special exception approval upon written request of the applicant received prior to its expiration.