You just need to select the rows to be deleted, and then delete them....see script below
Names Default To Here( 1 );
dt = New Table( "sample",
	Add Rows( 20 ),
	New Column( "Height",
		Numeric,
		"Continuous",
		Format( "Fixed Dec", 5, 0 ),
		Set Values(
			[59, 61, ., 66, 52, 60, 61, ., 60, 61, 56, 65, ., 58, 59, 61, ., 65, 63, 62]
		)
	),
	New Column( "weight",
		Numeric,
		"Continuous",
		Format( "Fixed Dec", 5, 0 ),
		Set Values(
			[95, 123, 74, 145, 64, 84, 128, 79, 112, 107, 67, 98, 105, 95, 79, 81, 91, 142, 84,
			85]
		)
	)
);
dt << select where( Is Missing( :Height ) == 1 );
dt << delete rows;
					
				
			
			
				
	Jim