I don't know. You can try to clear and start over.
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-onli...
Otherwise you will have to switch to the Desktop program to start over. You will need to download the .tax2019 file to transfer into a new Desktop return. Did you pay for online yet? If not you can buy the Desktop program here
https://turbotax.intuit.com/personal-taxes/past-years-products/
