Cancellation is the act of making something invalid or void, and can be done in a variety of ways. DISSOLUTION (11 letters) is the process of ending something, INVALIDATION (12 letters) is the act of making something invalid, NULLIFICATION (13 letters) is the act of making something legally void, REVOCATION (10 letters) is the act of taking something back, RETRACTION (10 letters) is the act of taking back a statement, ERASURE (7 letters) is the act of removing something completely, DELETION (8 letters) is the act of removing something from a list, REPEAL (6 letters) is the act of cancelling a law, ABROGATION (10 letters) is the act of cancelling a contract, REJECTION (9 letters) is the act of not accepting something, RENUNCIATION (12 letters) is the act of giving up a right, WITHDRAWAL (10 letters) is the act of taking something away, REVERSAL (8 letters) is the act of changing something back, Voided (7 letters) is the act of making something invalid, REVOKING (8 letters) is the act of taking something back, NEGATION (8 letters) is the act of denying something, ABOLITION (9 letters) is the act of ending something, ANNULMENT (9 letters) is the act of making something invalid, and Nogo (4 letters) is the act of not allowing something.