debits K_A's account by X units and credits K_B's account b…
debits K_A's account by X units and credits K_B's account by X units, unless this would create a negative balance in K_A's account in which case the message is ignored.
debits K_A's account by X units and credits K_B's account by X units, unless this would create a negative balance in K_A's account in which case the message is ignored.