structural:expansion, linguistic:translation
Principles

A land owner of an estate cannot give a "greater interest" in the estate than he or she owns. That is, a life estate owner cannot give complete and indefinite ownership (fee simple) to another person because the life tenant's ownership in the property ends when the person who is the measuring life dies. For instance, if Ashley conveyed to Bob for the life of Bob, and Bob conveys a life estate to another person, Charlie, for Charlie's life, then Charlie's life estate interest would last only until Charlie or Bob dies. Charlie's life interest or pur autre vie interest (interest for the life of another, whichever has applied) and most often the remaining rights of ownership in the property (the 'reversionary interest') devolve to the persons under the terms of the will/rules of intestacy/declaration of trust/trust deed (UK) or will/rules of intestacy/'grant or deed of life interest' (or similar) (U.S.) in remainder or revert to the original grantee, depending on terms of Ashley. Such a life estate in the U.S. can also be conveyed for the life of the grantor, such as "A conveys X to B until A dies" and in the UK by trust transferring upon trust or assigning rather than conveying X.