Name switching is:

the practice of a dealer attempting to replace one customer by a new one in a previously dealt transaction

the practice of a broker having to show a new name to the dealer, although he was full on the first name presented to him

the practice of a broker attempting to substitute a third name between the two original counterparties to clear the transaction

the practice of a broker attempting to show a substitution name to get out of a situation in which he was stuffed by a dealer