Check how much authority was actually delegated
A partner might agree that either adult can replace a broken kettle up to a given price. That rule does not necessarily cover a more expensive coffee machine, an ongoing subscription, or a trip that needs both adults’ time. Before acting without a reply, identify the decision, its cost, and the existing agreement that authorizes it. If the fit is unclear, say what needs confirmation rather than reading extra authority into a routine arrangement.
Use a temporary option only on its actual terms
If a deadline arrives first, look for a reversible action. You might request a free hold or give the host a provisional headcount. Tell the absent person exactly what was done and what remains open. Avoid spending shared money on an assumption that they would probably agree.
Explain exactly what remains open
If a venue offers to hold a table, ask whether it is free, when the hold expires, and whether a card guarantee or cancellation condition applies. A “hold” can have consequences the household did not authorize. Tell the absent adult the facts: “Table held without payment until noon; no booking yet. Please reply before eleven.” If a reply does not arrive, release it under the agreed terms and give the host only the attendance you can confirm.