How do I modify the AMT carryover amount. I go to deductions and credits. and amt but it just has the old number with no way to edit it.

Click on Start or Revisit next to Credit for AMT paid in a prior year and follow the instructions on the screen.   You will need your 2020 tax return to complete this section.  

Timing items are income or deductions that are reported for AMT on a different timeline than your regular taxes, the most common ones being incentive stock options (ISOs) and intangible drilling costs connected with an oil or gas activity. In these cases, sometimes income tax is paid faster or deductions are postponed over multiple years.   Examples include depreciation and passive activity losses.

If you paid AMT for any of the following common reasons, you probably don't qualify for this credit:

• High income (e.g., $523,600 for single filers and $1,047,200 for married filing jointly)
• High income and a large number of dependents
• High income and exercise of ISO’s or “private activity” bonds
• Large amount of property taxes