To correct your return, you must give us your daughter's correct name, social security number, and date of birth. We issue Notice CP12 when we correct one or more mistakes on your tax return, and: The overpayment is different from the one you expected.Learn how to write a letter to the IRS with our comprehensive guide and sample. Includes ChatGPT prompt. Send a typewritten letter to the IRS office that sent the notice. Use the format in the sample letter below. Access IRS forms, instructions and publications in electronic and print media. This notice provides taxpayers with information on the extensions of time to file returns and remit tax and the waivers from penalty and interest. Send a typewritten letter to the IRS office that sent the notice. Use the format in the sample letter below.