Final answer:
If the taxpayer and the IRS cannot agree after an appeals conference, the regional director of appeals will issue a 90-day letter, also known as a statutory notice of deficiency, giving the taxpayer 90 days to petition the U.S. Tax Court.
Step-by-step explanation:
If a taxpayer and the IRS cannot agree on the proposed adjustments after an appeals conference, the regional director of appeals will issue a 90-day letter. This letter, also known as a statutory notice of deficiency, gives the taxpayer 90 days to petition the U.S. Tax Court if they wish to dispute the proposed adjustments. It is an important step in the IRS appeal process and allows the taxpayer to have their case heard in court.