If you do not meet the requirements to be claimed by someone else and checked the box to indicate you can be claimed by someone else, you will have to prepare, print and mail an amended return form 1040X to uncheck the box. Do not uncheck it until you start the amended return. Here is a link to help you: https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed
An amended return must be printed and mailed. It can't be efiled. You must print and mail it yourself because TurboTax doesn't mail it for you. In normal times, the IRS takes about 16 weeks to process an amended return. You can track the status using this link: https://www.irs.gov/filing/wheres-my-amended-return
