The most common way to revoke a will is to execute a new one that states an intent to revoke all previously made wills. To revoke a will without making a new one, tear, burn, cancel, deface, obliterate or destroy it. This must be done with the intention of revoking it, and not done accidentally. If accidental, the will is not legally revoked.
Example: Ralph tells his son Clyde to go to the basement safe and tear up his (Ralph's) will. If Clyde does not tear it up in Ralph's presence, it is probably not effectively revoked.
What if you change your will by drafting a new one, but later decide you do not like the changes and want to go back to your old will? Can you destroy the new one and revive (bring back) the old one? Once you execute a new will revoking an old will, you cannot revive the old will unless you execute a new document stating that you intend to revive the old will. In other words, you must execute a new will.