Short answer. Yes. Under Article 1212 of the Civil Code, each solidary creditor may act unilaterally when what he does is useful to the others. No advance consent from the group is required as long as the act benefits — and does not prejudice — the rest of the creditors.
What the law says
Each one of the solidary creditors may do whatever may be useful to the others, but not anything which may be prejudicial to the latter.
Civil Code, Article 1212 — Useful and Prejudicial Acts of a Solidary Creditor. Read the full provision →
The permission to act alone
In a solidary obligation, each creditor holds the entire credit. That position carries a practical power: any one creditor can take steps that preserve or advance the common interest without convening all the others first. Article 1212 expressly allows this, limiting only acts that would harm the group. So if you are one of three solidary creditors and you want to interrupt prescription by making a formal demand on the debtor, you can do that on your own, and the effect runs in favor of all three.
Examples of useful acts
The article does not enumerate which acts qualify as useful — that is a practical question. Common examples include making a formal demand to prevent prescription from running, filing a case to collect the debt, preserving evidence, or requesting acknowledgment of the debt in writing. The touchstone is whether the act advances or protects what all the creditors are owed. An act that recovers the full amount, for instance, is useful even if the collecting creditor will later have to account to the others for their shares.
Who the rule binds
Article 1212 applies to every solidary creditor equally, not only to designated leaders or managing creditors. It also runs in both directions: the permission to act is available to any one of them, and the prohibition on prejudicial acts constrains all of them. A creditor cannot argue that a harmful act was justified because it was done in good faith, or that it was the most convenient course — the standard is whether the act benefited or prejudiced the others, not what the acting creditor intended.
The limit: useful but not prejudicial
The permission to act alone stops at the border between useful and prejudicial. A solidary creditor cannot, on his own, remit the debt, grant the debtor a significant extension of time, or do anything else that reduces what the others stand to collect. If your co-creditor has already done something that hurt the group without your consent, that is a different question — one governed by the same article's prohibition on prejudicial acts, with potential remedies available to the creditors who were harmed. What is and is not prejudicial in a specific arrangement often requires careful legal analysis.