put https://{environment}.{server}.com/v3/transaction/
Once a transaction has been voided, it will not show up on the customer's credit card statement. Customers who have online banking that allows them to see 'Pending' transactions may see the voided transaction for a few days before it disappears.
You can only void a transaction that hasn't been settled yet. A transaction is settled when the batch that it is in has been closed. If the transaction has been settled, you must run a refund instead using a void transaction. If you run a credit, both the credit and the initial charge will show up on the customer's credit card statement.
You can void a transaction by putting the original transaction with a type of 'void'.