You must notify the Minnesota Department of Revenue within 180 days. Many find the easiest way to figure the entries for Form.X is to first make the changes in the margin of the return they are amending. You can check the status of an amended return around 3 weeks after you submit it. You should generally allow 8 to 12 weeks for your Form 1040-X to be processed. For all estate tax matters, submit Form ET-14, Estate Tax Power of. Attorney, instead of Form POA-1. Below are resources to help you determine your tax status, file your tax returns, and answer taxrelated questions. To request a conference, complete page 1 of this form and fax to. Search for Tax Return Preparers.