You're required to fix or correct (amend) your Virginia return to reflect the changes on your federal return within one year of the final determination date. Send a typewritten letter to the IRS office that sent the notice.Use the format in the sample letter below. You can find the CP or LTR number on the right corner of the letter. You'll need a copy of your most recently filed Virginia tax return to enroll. You generally have 30 days to respond to an IRS notice, so there's no reason to ignore it. Always check which tax year the notice relates to. Taxpayers need to sign Form 3870 only when they have not already provided a signed written request for reconsideration. We have provided sample letters that you can use to request waivers of several different types of IRS penalties.