Nope. That is not operational yet nor is there any word yet on when it will be implemented. Not sure where you saw August 1.
You have three years from the deadline to file an amended return. You can mail it now or wait for the e-filing option later--we do not know when that will be.
https://www.irs.gov/newsroom/irs-announces-form-1040-x-electronic-filing-options-coming-this-summer-...
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