Answer
Collation is the process by which a compulsory heir who received property from the decedent during the decedent's lifetime — by donation or other gratuitous title — brings its value back into the estate mass, so that the legitime of each heir can be computed and the advance charged against that heir's share (Civil Code Articles 1061 to 1077). A donation to a compulsory heir is treated as an advance on the legitime unless the donor expressly provided otherwise or it came from the free portion.
Once the estate is settled it is divided among the heirs by partition, which may be judicial or extrajudicial (Article 1078 and following). Co-heirs owe one another a reciprocal warranty for the title and quality of the property allotted, and a partition may be rescinded for lesion or annulled for fraud or mistake.