California defines an “obligation” as “a legal duty, by which a person is bound to do or not to do a certain thing.”  Cal. Civ. Code § 1427.  An obligation is created in one of two ways: by contract or by operation of law.  Cal. Civ. Code § 1428.  The Civil Code, however, provides six different means to extinguish an obligation:

• Performance (§§ 1473-79)
• Offer of Performance (§§ 1485-1505)
• Prevention of Performance or Offer (§§ 1511-15)
• Accord and Satisfaction (§§ 1521-26)
• Novation (§§ 1530-33)
• Release (§§ 1541-43)

There are a number of conditions are limitations on each of these.  For example, the Civil Code provides that an offer of partial performance is of no effect and that the offer must be made by the debtor, or by some person on his behalf and with his assent.