Changing from single to married filing separately is probably going to mean that you will have to pay additional tax. Are you doing this because you were actually married as of December 31? If so, you have to change it. But is there any possibility of filing as married filing jointly with your spouse? That would save money for both of you.
xmasbaby0 gave you a link to the FAQ for instructions to amend a tax return that you filed with TurboTax. (The FAQ says "prior year" but it also works for 2022.) Let me just add a few other pointers.
Before you start to amend your return in TurboTax Online, be sure to download a PDF of your original tax return and save it on your own computer. Once you amend it, you will no longer be able to access the original in TurboTax.
The IRS says it is currently taking 20 weeks or more to process an amended return.
If you filed a state tax return, you will have to amend that as well.
In some cases it could be possible for your spouse to file as head of household, even if you file as married filing separately. We can't say whether that's a possibility because you have not given any information about your spouse's situation.
