Short answer. No. Under Article 1084 a voluntary heir whose share depends on a condition cannot demand partition until the condition is fulfilled. The other co-heirs may go ahead and demand partition, but they must give sufficient security for the conditional heir's rights, and until the condition's fate is known, that partition is treated as merely provisional.
What the law says
Voluntary heirs upon whom some condition has been imposed cannot demand a partition until the condition has been fulfilled
Civil Code, Article 1084 — Conditional Voluntary Heirs. Read the full provision →
A conditional heir must wait
When a testator gives to a voluntary heir subject to a condition, that heir's right does not become certain until the condition happens. Article 1084 draws the natural consequence: voluntary heirs upon whom some condition has been imposed cannot demand a partition until the condition has been fulfilled. Since it is not yet settled whether the conditional heir will actually take, he cannot force the estate to be divided on the strength of a share he may never receive. His demand for partition waits on the fulfilment of the condition attached to his gift.
The other co-heirs may proceed with security
The estate is not frozen in the meantime. The other co-heirs, whose rights are not conditional, may demand partition without waiting. But they cannot simply ignore the conditional heir. The law requires them to give sufficient security for the rights the conditional heir may have if his condition is later complied with. This lets the unconditional heirs move forward and enjoy their shares while protecting the conditional heir's potential interest, so that a fulfilled condition later will find his share preserved rather than dissipated.
The partition is provisional until the condition is resolved
A partition made under these circumstances is not treated as final for all purposes. Until it is known that the condition has not been fulfilled or can never be complied with, the partition is understood to be provisional. It holds the estate in a workable state while the condition remains pending, subject to adjustment once the outcome is known. If the condition is met, the conditional heir's share is carved out; if it fails, the provisional division firms up among those who were entitled without it.
What this means in practice
For a conditional heir, the practical message is patience backed by protection: he cannot compel a division yet, but the law shields his eventual share by requiring security from those who do divide. For the other heirs, it is that they may proceed, but only if they secure the conditional heir's contingent rights and accept that the arrangement stays provisional for now. This balance keeps an estate from being held hostage by an unresolved condition while ensuring no one is quietly written out of what may still fall due to them.