Assign (rights) refers to the legal transfer of specific rights from the copyright holder (i.e. an author, performer) to another (i.e. music publisher, record label, etc.). As opposed to licensing which grants a temporary use of rights, the assignment is considered a permanent transfer, in effect a “sale” of rights (1). This transfer is fixed in an agreement, which details the scope and conditions of the rights being transferred. In the EU, the moral rights of an author or a performer cannot be transferred at all (with the exception in the case of inheriting the rights) and the assignment can therefore only refer to transferring the economic rights (2). 

In some countries, personal rights can be waived (such as Canada) (3), but in the EU, “moral rights are usually not assignable and can be waived only to a limited extent” (4). However, in practice, personal rights are often de facto transferred via exclusive licence to use them until the end of their term.