A plan uses what you know now. Leave a realistic way to respond when information or circumstances change.
Identify the commitments with little room for adjustment and the work that can move. Keep those differences visible. A schedule filled entirely with fixed promises has limited capacity to absorb an unexpected responsibility.
Choose the response route
In a fictional project, an essential reviewer becomes unavailable. Decide who can authorise a different review, whether an interim result would be useful and which affected person needs an update. Having those questions ready makes the response more deliberate.
Avoid treating every uncertainty as a reason to postpone beginning. Some questions can be resolved through a small reversible attempt. Others require confirmation before work responsibly proceeds. Match the response to the consequence.
After an interruption, review whether it was truly unforeseeable. A repeated event may deserve a normal place in the plan. Preserve the learning without pretending you could have predicted every detail. A useful plan offers both a chosen direction and a credible method of adapting when reality supplies something different.