Note: You must complete a separate Form 3911 for each refund for which you are requesting information. Use Form 843 to claim a refund or request an abatement of certain taxes, interest, penalties, fees, and additions to tax.TRS recommends that you submit the completed Form W-8BEN with your TRS 6 in order to expedite the processing of your refund. Check the box below that indicates your reason for filing Form 843. Tax. Abatement or refund of tax other than income, estate, or gift tax. A taxpayer must apply for a refund within three years of making the payment. We have provided sample letters that you can use to request waivers of several different types of IRS penalties. Find self-help tools to help you with your tax issues. The primary letter we use to request information about a return is Form DTF948 or DTF948O, Request for Information (RFI). There is no IRS form that can be used to request this type of relief.