Final answer:
Once a record reversal is determined to be necessary and a freeze code is assigned, the next step is to notify your supervisor for review and further instructions.
Step-by-step explanation:
After determining that a record reversal correction is needed and assigning a freeze code "Q" to all affected item records, the next step you should take is to notify your supervisor. This action is part of the internal controls and audit trails within an organization, ensuring that any amendments to financial or other critical records are overseen and authorized by a higher authority. Once you have notified your supervisor, they will review the situation and provide further instructions on how to proceed, which may include re-entering data, submitting a report, or other steps depending on your organization's policies.