Change IRA selections here:
*Federal Taxes,
*Deductions & Credits,
*I’ll choose what I work on (if that screen comes up),
*Retirement & Investments,
*Traditional & Roth IRA contribution.

OR  Use the "Tools" menu  (if online version under My Account) and then "Search Topics" for "ira contributions" which will take you to the same place.

Uncheck the Traditional IRA box then press continue.  The interview will ask if you want to remove the Traditional IRA contribution, say yes and it should be deleted.  Return to the beginning and check the Roth box and continue to enter the Roth contribution.