How do I change filing status?

What tax year are you trying to make that change for?   2022---or 2021?   You cannot change it for 2021---you are not allowed to change a joint return to separate returns after the filing deadline for the tax year.

As xmasbaby0 stated, you can only change the filing status to Separate for a previously filed return if it is before the due date of the return.

If you are preparing a 2022 return, and both of your parents passed away in 2022, then a joint return could be filed for both of them. The IRS considers someone married for the entire year that their husband or wife died if they don't remarry during that year. 

Enter all of the information including the date of death for both taxpayers in the My Info / Personal Info section. This is also where you are given the option to file jointly or separately.

The filing of the deceased taxpayer's final return usually falls to the executor or administrator of the estate, but if neither is named,  then the task needs to be taken over by a survivor of the deceased. The final return is filed on the same form that would have been used if the taxpayer were still alive, but "Deceased:" is written at the top of the return followed by the person's name and the date of death. The deadline to file a final return is the tax filing deadline of the year following the taxpayer's death.

Report all income up to the date of death and claim all eligible credits and deductions. 

Please see this TurboTax article and this IRS webpage for more information.

@jpmitchelljrsing