Final answer:
A high-integrity professional acknowledges an unintentional error, apologizes for it, and takes action to correct it. The only action they do not take is refusing to do further business with the client.
Step-by-step explanation:
When an "unintentional error" occurs, a high-integrity professional does all of the following EXCEPT refusing to do further business with the client. A high-integrity professional will indeed acknowledge the error, offer an apology for the mistake, and take action to correct it. Rather than refusing to do further business, a professional of high integrity is more likely to try to restore the client's trust and ensure the error does not occur again.