In general, solidarity of an obligation is never presumed, and it must be expressly stated as the true intent of the parties' will.
Contractual solidary obligations are frequently created by insurance policies or co-signing a loan.
A common example of a solidary obligation created thorough operation of law is vicarious liability such as respondeat superior.
A solidary obligation that is active exists among the obligees (creditors) in the transaction.
The origin of solidarity can be traced to a Roman idea known as correality where a single thing was owed by more than one person.
There was a transformation and growth of this idea during the ius commune before being codified in the Napoleonic Code of 1804.
Generally, full payment to any of the solidary obligees extinguishes the obligation.
A common example of solidary obligations for the obligees is a joint bank account; when two or more names are on an account, they are obligees of the bank's obligation to make funds available on demand.
When one co-signs a loan for another, they both become solidary obligors in relation to the debt owed.
Since passive solidarity is mainly a guarantee and benefit for the creditor or obligee, he may renounce it at his pleasure.
If he renounces solidarity for only one of the obligors, this has the important effect of preserving his right to demand the whole performance from the remaining obligors bound in solido, minus the portion owed by the one whose solidarity was renounced.
Under the Louisiana Civil Code, an obligee who received a partial performance from an obligor separately will still preserve the solidary obligation against all of the obligors after deduction of that partial performance.
Unlike the renunciation of a solidary debt, a cancellation affects the object of the entire obligation.
Assume that X renounces solidarity in favor of A, who pays X $2,500, and that B thereafter goes bankrupt.
This means that although the unconcerned parties may be forced to pay the obligee some or all of the money, they can seek the entirety of their contribution from the concerned obligor in full.