First you would have to exactly recreate the original return (is it for 2020?) in TT, then fool the system by saying you are going to file it by mail (but don't actually do so). Then come back at the end of March when the 1040-X amended return form is ready here. But I don't know if you will then be able to efile the amended return through TT since you did not efile the original return with them. You might have to file by mail.
CAN I USE TURBOTAX TO AMEND IF THE RETURN WAS PREPARED SOMEWHERE ELSE?
If you did not use TurboTax to prepare your tax return, it is possible to amend the return using TurboTax but it will really be a pain. It would be better to use the software or service used to file originally. If a paid preparer made a mistake on your tax return, that tax preparer should do the amended return for you at no charge.
In order to use TurboTax to amend your return, you need to purchase the desktop software for the tax year and re-create the return EXACTLY as it appeared when it was filed with the IRS/states. Every line has to be the same. Then you have to "trick" the software into thinking you filed by saying you will mail the return. (but do not mail it) AFTER that, you use the software to prepare a Form 1040X, which has to be printed, signed and mailed to the IRS. It takes the IRS about 3-4 months to process an amended return
If you are asking about amending a 2020 tax return the 1040X will not be available in the software until March 25--subject to change.