Deductions & credits

I followed directions to choose the itemized deduction.  Turbotax will NOT enable the change to itemized deductions.  I am single, have over $16000 of itemized deductions vs. $12,200 of standard deduction.  I owe no state income tax so I want to use the sales tax option instead.  Turbotax will not allow this option using the sales tax tables.  Instead it includes what would be allowed for sales tax deduction under personal property tax deduction.  I do not know how to change this and I want my return to be accurate.