How is a negative transaction handled when a corporate card payment is canceled?

How is a transaction handled when a corporate card payment is canceled and a negative amount is generated?

There are situations where negative-amount transactions occur due to cancellations or adjustments after a corporate card payment has been made.
I have the following two questions:

① Is it possible for an employee to submit a negative-amount transaction on an expense report?
By default, negative-amount transactions are not displayed on the employee expense entry screen. Is there any way to enable the submission of negative-amount expenses?

② If the answer to question ① is yes, will the negative-amount transaction be offset against the payment to the card issuer in Accounts Payable (AP) automatically