My LLC is no longer a partnership, how do I change that on Intuit?

You should file a final tax return for the partnership through the date it ended and going forward enter your business income in the self-employed income section in TurboTax. The partnership return would be prepared using the TurboTax Business product and then going forward you will use the TurboTax Home and Business product to prepare your business Schedule C that will be included in with your personal Form 1040 filing.

I believe we need a few more facts to respond to your question.

While state requirements may vary, it is possible for a PLLC to have a single owner.

So exactly how was your original PLLC structured?  Sole owner? Multiple owners?

What changed and when?

How was the change handled?