Short answer. The depositary may change the method of keeping your things only if the circumstances reasonably suggest you would consent if you knew the facts, and only after notifying you and waiting for your decision. The one exception is when delay would cause danger — in that situation, the depositary may act first without waiting.
What the law says
The depositary may change the way of the deposit if under the circumstances he may reasonably presume that the depositor would consent to the change if he knew of the facts of the situation. However, before the depositary may make such change, he shall notify the depositor thereof and wait for his decision, unless delay would cause danger.
Civil Code, Article 1974 — Change in the Manner of Deposit. Read the full provision →
The default rule: notify and wait
Article 1974 sets a clear two-step requirement before a depositary can change how your property is stored: notify you and wait for your decision. The depositary cannot simply decide on their own that a different method is better and implement it without telling you. This protects your right to control how your property is handled. The notification requirement is not a mere formality — you are entitled to make the call, or at least have the opportunity to make it.
The threshold for even considering a change
The depositary can only consider changing the method at all if the circumstances are such that they can "reasonably presume" you would consent if you knew the facts. This is an objective standard, not simply what the depositary personally thinks is better. A change from one storage room to another of equal security would likely pass this test. Moving your valuables out of a locked cabinet into an open shelf would almost certainly not. The depositary must honestly ask: knowing what I know about this situation, would a reasonable depositor in this person's position agree?
The emergency exception
The only scenario where the depositary can act without waiting for your response is when delay would cause danger. If your stored goods are at risk of flooding, fire, or spoilage and there is no time to reach you, the depositary may act immediately to protect the property. This exception is narrow — it requires actual urgency, not mere inconvenience or preference. After taking emergency action, the depositary should still inform you of what happened and why as soon as possible.
What you can do if the depositary changed the method without authority
If the depositary changed how your property was kept without notifying you, without emergency justification, and without a reasonable basis for presuming your consent, they have exceeded their authority. If that unauthorized change then leads to loss or damage, they may be liable for it. Even if no loss occurred, you are entitled to insist that your property be kept in the manner originally agreed. You may also demand its return immediately if you no longer trust the depositary's judgment over your property.