In TurboTax (TT), enter at:
Federal Taxes Tab (Personal for H&B version)
Deductions & Credits
-Scroll down to:
--Education
--ESA and 529 Qualified Tuition Programs (1099-Q)
Click on Update
On the next screen, click no to the question "Did you receive a 1099-Q"
The next screen will ask you to confirm removal of the previously entered 1099-Q
Note: I have download (desktop) TurboTax (TT). I have not confirmed if it works the same way in online TT (TTO).