How do you handle a PhD student who wants to change their thesis topic?

I supervise a second-year PhD student in educational management who now wants to shift from school leadership to higher education governance.

The new direction is defensible, but it would mean rebuilding the literature review and possibly the methods.

I am torn between protecting their timeline and supporting a topic they are genuinely motivated by.

How have you handled a major topic change mid-PhD, and what did you agree with the student?