How can I amend a 2020 tax return to remove a dependant so they can collect stimulus?

[JLS81]

I just claimed my adult son as a dependent on my 2020 return. With the new stimulus law just signed, we are not eligible for stimulus, but would be if we did not claim him. Claiming him as a dependent makes him ineligible.

How can I amend my return to remove him as a dependent?

Is there a timetable for TurboTax to have the amended section (for form 1040x)? How long would it be for him to receive his stimulus?

[DoninGA]

Why do you think you will not receive the third stimulus payment if you claim your son as a dependent?

IRS website for the third stimulus payment information - https://www.irs.gov/newsroom/more-details-about-the-third-round-of-economic-impact-payments

How much is the third Economic Impact Payment?

Those eligible will automatically receive an Economic Impact Payment of up to $1,400 for individuals or $2,800 for married couples, plus $1,400 for each dependent. Unlike EIP1 and EIP2, families will get a payment for all their dependents claimed on a tax return, not just their qualifying children under 17. Normally, a taxpayer will qualify for the full amount if they have an adjusted gross income of up to $75,000 for singles and married persons filing a separate return, up to $112,500 for heads of household and up to $150,000 for married couples filing joint returns and surviving spouses. Payment amounts are reduced for filers with incomes above those levels.

[JLS81]

Because we exceed the AGI maximum allowable, thereby making him ineligible based off our earnings.