Clear your tax return and start over. Do not attempt to change the order of the names on a joint return. Trying to do so will cause numerous errors in your tax return that you will never be able to fix.
See the instructions at the following link to clear your return and start over in TurboTax Online.
https://ttlc.intuit.com/questions/2586254-using-clear-start-over-in-turbotax-online
