After being told

Every piece of supposed evidence AGAINST God, the flood, or the creation is based on made-up stories, arbitrary assumptions, irrational statements, or outright lies.

The ungodly person tries to reverse the statement as though it were arbitrary. However, you have just told them that the evidence for God, the flood, and the creation is revelation. God reveals it to you. He speaks to your innermost being and lets you know He is with you. He speaks to you in guidance, showing you the difference between right and wrong. He speaks to you through the Bible about the history of the world and all that He has done. So this is not reversible.

If you had said, "You are stupid," that is reversible. If you had said, "I disagree with you," that is reversible. When you say something that is reversible, you have said something that you should not have said.

Here is one way you could answer:

Now, please let me ask you a question about a claim that you made: "every piece of supposed evidence FOR God, the flood and the creation is based on made-up stories, arbitrary assumptions, irrational statements and outright lies." I have told you that I know this by revelation from God. Everyone who follows Jesus is led by Jesus. As Jesus says, "My sheep hear My Voice." And, "Whoever is on the side of Truth listens to Me." Christian is a word that means different things to different people. Some of those people are actually following Jesus and being led by Him. Jesus reveals Himself to us. Jesus reveals to us that the Bible is God's Word and that it is without error and that God speaks to us through the Bible. And the Holy Spirit does speak to us through the Bible. And He tells us that the flood and creation happened. He also tells us that in the last day there will be some people who are willingly ignorant who will deny the creation, the flood, and the coming judgment. Just think, you get to fulfill God's prophetic word. (some caveats about hearing God's Voice)

Now, here is my question: Do you know of any conclusive evidence for your claim against God, the Flood, the Creation, or the Biblical historical account that is NOT based on made-up stories, arbitrary assumptions, irrational statements, or outright lies? Please don't come back with stories that are based on many arbitrary assumptions such as materialism, naturalism, or uniformitarianism. Please don't come back with irrational things like bandwagon arguments, straw-man arguments, or just emotional name-calling. I get a lot of that, but I would like to hear an answer even if that answer is simply, "I don't have any evidence without assumptions or stories, but this is what I prefer to believe."

What do you say if they reject Christ and just want to argue?

See the baloney detector for more information.