Yes , you can amend your tax return using TurboTax if your original return was down elsewhere. However, you will have to recreate the original return exactly as it was filed as part of this process.
You would first have to fill out a new return in TurboTax like you were doing it for the first time and hopefully come out with the same results as your original filed return. Then when it exactly matches what you filed and amounts are the same for every line on the 1040 tell TurboTax you want to file by mail and print out the original return so TurboTax thinks it was filed, then you can do the amended return.
Please see this TurboTax FAQ for more information about filing an amended return: https://ttlc.intuit.com/replies/6603004
