Request pursuant to 11 DCMR § 3104.1 for a special exception under § 223, not meeting the minimum lot area and width requirements under § 401, the rear yard requirements under § 404.1, and the open court requirements under § 406.1, to allow the expansion of a third-story to convert an existing three-story, one-family dwelling into a flat in the R-4 District at premises 1826 12th Street N.W. (Square 275, Lot 51).