I’ll break it down for you.
A guy on the witness stand, or in a science journal, declares that x because of p. (Where x is the truth claim based on p, the evidence.)
Then p is shown to include no physical evidence, so the guy changes his mind and says no, I didn’t mean x, I meant y.
He’s making things up, known as lying.
That’s not the same as changing a theory due to new evidence. Investigators do it all the time. Scientists do it all the time. The only people who try to change evidence to fit theory are demagogues, zealots and frauds.