This is much more difficult than it seems.
To pivot means that your previous assumption was incorrect. It means admitting you were wrong. Or maybe it's you merely changing your opinion based on new information, which means you were as correct as you could be. Changing directions like this isn't even the hardest part. The challenge will come when others are involved.
What will they think? What will they say? How will I ever explain this to them? I can't simply say "I changed my mind."
Try this: "We did the best we could with the information we had, then because we continued to test, learn and grow, we received new information that will allow us to make an even more important decision."
When it comes to pivoting when it counts, making the right decision should always trump avoiding embarrassment.