Definition
to undergo changes over time until the ultimate outcome is determined
At the early stages of our planning, we are unsure how the final outcome will shake out, as we need time to see how things develop.
In the election, the candidates' support rates shook out with fluctuations until just before the voting day, when the results finally became apparent.
The plot of the movie shook out during the filming process, and the story of the final product gradually became clearer.