The easiest way to not claim her is delete her from TurboTax. Otherwise the only way to not claim her is lie to TurboTax when it asks you all the dependent questions. Lying to TurboTax to get it to do what you want does not constitute lying to the IRS.
But, what are you trying to accomplish by not claiming her? What ever it is, it won't work. On her return, she must check the box that says she CAN be claimed by someone else. That makes her ineligible for stimulus money (recovery rebate credit).
There's a new urban myth among college students that says they can get a $1000 from the government just for filing a tax form. For most of them, they simply aren't eligible. A full time unmarried student, under age 24, even if you don't qualify as a dependent, is only eligible for the refundable portion of the American Opportunity Credit if he supports himself by working. You cannot be supporting yourself on parental support, 529 plans or student loans & grants. You usually must have actually paid tuition, not had it paid by scholarships & grants. It is usually best if the parent claims that credit.
Reference: Line 7 instructions for form 8863. https://www.irs.gov/instructions/i8863
Furthermore, there is a rule that says IF somebody else CAN claim him as a dependent, he is not allowed to claim himself. If he has sufficient income (usually more than $12,400), he can & should still file taxes. In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section. TT will check that box on form 1040.
Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.
