A more thorough explanation:

Common recovery is a legal process that was used in the past to transfer land ownership. It involved a tenant in tail disentailing a fee-tail estate. The process was full of legal fictions and was abolished in the early 19th century.

The process allowed a potential transferee who was barred by law from receiving land to "recover" the land by suing the actual owner. This was done by bringing a real action against the owner, claiming falsely that the claimant owned the land and demanding recovery of it. The owner would then respond by claiming falsely that they had acquired the land from someone else and that the person had warranted title to the land. The person who warranted title would then admit falsely that they had done so. The result of this process was to leave the claimant with title to the land in fee simple and to leave the owner with a judgment against the person who warranted title.

For example, if A owned a piece of land in fee tail, but wanted to sell it to B who was barred by law from receiving land, A could use common recovery to transfer the land to B. A would collude with B and C, who had no land, to bring a real action against A claiming that B owned the land. A would then claim that they had acquired the land from C and that C had warranted title to the land. C would admit falsely that they had warranted title. B would then take a default judgment against A for the recovery of the land, and A would obtain a default judgment against C for the recovery of land of equal value. The result of this process was to leave B with title to the land in fee simple and to leave A with their judgment against C.

Common recovery was originally concocted by the clergy as a way to avoid the land-conveyance restrictions imposed by mortmain acts.