Original sentence: Also, if a player opens, raises, or jumps to 4H/4S without any preceeding cuebids, 4NT by his partner is Blackwood or RKC.The immediate advantage of this approach over  Blackwood/RKC , is that while still establishing the combined number of keycards,.This convention applies when 4NT is preceeded by  cuebids, and generally when 4NT is a non-jumping bid
Edited sentence: Also, if a player opens, raises, or jumps to 4H/4S without any preceding cuebids, 4NT by his partner is Blackwood or RKC.The immediate advantage of this approach over Blackwood/RKC, is that while still establishing the combined number of keycards,.This convention applies when 4NT is preceded by cuebids, and generally when 4NT is a non-jumping bid