The IS auditor should inform audit management of the earlier involvement in designing the application. This is to ensure that there is no conflict of interest or bias that may affect the objectivity or independence of the audit. Audit management can then decide whether to assign a different auditor or to proceed with the same auditor with appropriate safeguards. The other options are not appropriate for the IS auditor to do in this situation. Refusing the assignment to avoid conflict of interest is an extreme measure that may not be necessary or feasible, especially if there are no other qualified auditors available. Using the knowledge of the application to carry out the audit is risky, as it may lead to overlooking or ignoring potential issues or errors in the application. Modifying the scope of the audit is not advisable, as it may compromise the quality or completeness of the audit. References: CISA Review Manual (Digital Version), Chapter 2, Section 2.1