You will need to complete an amended tax return, Form 1040X, for tax year 2014. Since you paid the CPA to complete your 2014 tax return then they should also complete your amended tax return. An amended tax return can only be printed and mailed to the IRS.
IRS Form 1040X - https://www.irs.gov/pub/irs-pdf/f1040x.pdf
IRS Form 1040X instructions - https://www.irs.gov/pub/irs-pdf/i1040x.pdf
To use the TurboTax software to complete an amended tax return that was not completed using TurboTax can be complex. You would first have to purchase and download the TurboTax 2014 software to be installed on your personal computer. You would then have to exactly recreate the 2014 tax return that was filed to include any errors or mistakes on the return. Then save the return to be printed and mailed to the IRS so the software knows the return has been completed. After that you then can begin the process to amend the tax return.
Go to this TurboTax website to purchase and download one of the 2014 desktop editions - https://turbotax.intuit.com/personal-taxes/past-years-products/
You will need to complete an amended tax return, Form 1040X, for tax year 2014. Since you paid the CPA to complete your 2014 tax return then they should also complete your amended tax return. An amended tax return can only be printed and mailed to the IRS.
IRS Form 1040X - https://www.irs.gov/pub/irs-pdf/f1040x.pdf
IRS Form 1040X instructions - https://www.irs.gov/pub/irs-pdf/i1040x.pdf
To use the TurboTax software to complete an amended tax return that was not completed using TurboTax can be complex. You would first have to purchase and download the TurboTax 2014 software to be installed on your personal computer. You would then have to exactly recreate the 2014 tax return that was filed to include any errors or mistakes on the return. Then save the return to be printed and mailed to the IRS so the software knows the return has been completed. After that you then can begin the process to amend the tax return.
Go to this TurboTax website to purchase and download one of the 2014 desktop editions - https://turbotax.intuit.com/personal-taxes/past-years-products/
You have to respond to the IRS notice that you received. Did the notice say that you can include an amended return with your response? If not, it might not be necessary or helpful to amend. If you do prepare an amended return, send it to the address specified in the IRS notice, together with the other parts of your response. Do not file the amended return separately.
But the better approach, as DoninGA suggested, would be to go back to the CPA who prepared the return, and bring the IRS notice. The CPA should prepare a response to the IRS notice for you, and prepare the amended return if needed.