If the Decision Owner Is Unavailable, What Can Move?

Imagine a critical work decision can’t wait, but the person who normally owns it is unavailable. A backup who has no agreed authority may hesitate; a backup who assumes too much may commit the team to a course nobody approved.

How should teams decide in advance which choices a backup can make, which need consultation, and which must wait? What should define that boundary: how reversible the decision is, its impact on customers or resources, or something else?