This is more difficult than it sounds.
To some people, it means admitting you were wrong.
(But of course, you weren’t wrong. You made a decision based on one set of facts, but now you’re aware of something new.)
To some people, sunk costs (a cost that has already been incurred and cannot be recovered) are a real emotional hot button, and walking away from investments of time, of money, and mostly, of commitment, is difficult.
(But of course, ignoring sunk costs is a key to smart decision making).
And, to some people, the peer pressure of sticking with the group that you joined when you first made a decision is enough to overwhelm your desire to make a better decision. “What will I tell my friends?”
A useful riff you can try:
Sure, I decided that then, when I knew what I knew then. And if the facts were still the same, my decision would be too. But the facts have changed. We’ve all heard them. New facts mean it’s time for me to make a new decision, without regard for what I was busy doing yesterday, without concern for the people who might disagree with me. My guess is that once they realize these new facts, they’re likely to make the same new decision I just did.
This decision is more important than my pride.