FEDERAL Minister for Railways Ghulam Ahmed Bilour said that the 18th constitutional amendment could not be approved by the National Assembly unless the issue of renaming NWFP was resolved, reported a private TV channel on Sunday. The Parliament will not endorse the 18th amendment till the matter of renaming NWFP is settled, Bilour said while talking to newsmen after addressing a mass gathering at Tehsil Gorgatri near Peshawar on Sunday.