Final answer:
An RAR is a Revenue Adjustments Report used in business to explain proposed adjustments to revenue and list the balance due or overpayment.
Step-by-step explanation:
An RAR stands for Revenue Adjustments Report, which is a document used in business to explain proposed adjustments to revenue and to list the balance due or overpayment. It serves the purpose of reporting changes to existing laws and offers an estimate of the cost for implementation.