My 2018 return was accepted by IRS. Turbo Tax errored and entered higher than standard deduction. How to correct this error. this will increase tax due.

noticed that Sch A is not filed.  and Line 8 shows 26,600 instead of 24,000.  

So my taxable income is reported short by 2,600.    This was passed by "Smart Check"  and Turbo tax filed it.  I do not want to wait for IRS to bill me for the error.

I have to pay additional amount.