Update the structure when the client's objective materially changes, but you do not need to restart the entire case.

State what changed and which parts of your original structure are still useful. Then reprioritize the analysis around the new objective.

This is a chance to show adaptability. A structure should guide the work, not become a fixed template.

Keep the revision concise. The interviewer wants to see that you can redirect the problem-solving path. For a deeper explanation of how a structure should evolve with the problem, see the case structure vs. framework guide.

I used to cling to the original framework too long. Saying what changed out loud helped.