I asked AI what is "conditional acceptance" in taxes...

it said:

In the context of taxes, conditional acceptance can be used to challenge a tax liability or demand. For example, if the IRS sends you a notice that you owe $5,000 in taxes, you can reply with a conditional acceptance that says you will pay the amount if the IRS provides proof that you are liable for the tax and that the amount is correct. This way, you are not rejecting the offer or admitting to the debt, but rather asking for more information or evidence before you agree to pay.
Conditional acceptance can also be used to request an extension or a waiver of penalties for filing or paying taxes late.