Assignment is a legal concept that refers to the transfer of rights from one person to another, and in common law [old British wig-wearing lawyer law] an assignment clause will transfer both the rights and the duties of an existing contract. See Corvallis R. Co. v. Portland Ry. Co., 84 O4 524 (1917). Assignment of rights under a contract does not, however, delegate the duties of the assignor [person assigning the contract] unless the assignee [person taking over the contract] agrees to assume the duties. An assumption agreement is basically the reverse of an assignment agreement. While assignment shows that one party desires to legally give their rights to another person, an assumption agreement shows that one party desires to legally take the rights from another person. They work together, creating a seamless transfer of obligations from one person to another.
The basic rule in contract law is that any contractual right and duty can be transferred to another person. Provisions that restrict assignment are legal, but these anti-assignment clauses must be absolutely clear.
In the Oregon REALTORS® Sale Agreements, there is an assignment clause that reads, “Buyer may not assign this Agreement, or Buyer’s rights hereunder, without Seller’s prior written consent, unless the Parties indicate that assignment is permitted by the addition of “and/or assigns” on the line identifying the Buyer on the first page of this Agreement.” In other words: no assignment unless, either 1) the Buyer is described as “Buyer, and/or assigns” in sale agreement, or 2) the Seller otherwise provides permission in writing.
Assignment and assumption also pops up in the tenant related clauses. If a Buyer is planning to purchase tenant-occupied property and become a landlord, the Seller has to give over the landlordship reins to the Buyer. Otherwise, the tenant may still legally recognize the Seller as the landlord, even though the Buyer owns the land. Assignment to the Buyer gives the Buyer the rights to be the landlord, to collect rent, evict tenants, to do repairs when tenants demand it. Assumption by the Buyer takes the rights from the Seller, affirming that the Buyer intends to be the landlord and is taking over all of the rights that Seller owed the tenants.