A project can continue by inertia even when the expected result has become unlikely. The review must focus on future activities and available alternatives. The work already done helps to understand the situation, but does not guarantee that continuing is the most useful choice.
I propose to define in advance some moments of verification and the necessary information. If an essential condition changes, a new assessment is needed. The comparison should include the possibility of reducing the project or retaining some of the work that remains usable.
Let's imagine a business initiative that requires a partner who is no longer available. Continuing in the same format can generate costs without resolving the constraint. A smaller format could be achievable, or closure could free up resources for a commitment already required by customers.
The decision must be communicated to the persons involved with responsibilities and understandable steps. Closing also requires work: completing commitments and keeping useful information. A well-conducted review makes it possible to interrupt what has lost usefulness without dispersing how much it can serve subsequent activities.