A person who makes a will (a testator) may update or revise the will at any time during their lifetime if the testator has the required mental capacity (is of sound mind) and the document is executed or signed with the required formalities (such as witnesses and signatures), as provided by the state’s laws.

There are generally two ways to update a will—execute a new will (usually the best option) with the required witnesses, signatures, and other formalities—or execute a codicil (a supplement to an earlier will), with the required witnesses, signatures, and other formalities, as provided by the state’s laws.

Laws regarding the use of codicils and the required formalities for wills and codicils vary from state to state and are usually located in a state’s statutes—often in the estates code or probate code.

A testator who updates their will by executing a new will should usually destroy the previous will to avoid questions regarding which will reflects the testator’s true intent and to avoid competing wills being offered for probate (recognition by the court).

In Colorado, a testator has the right to update or revise their will at any time as long as they have the mental capacity to do so and adhere to the state's legal formalities. To update a will, the testator can either create a new will or add a codicil to the existing will. Both methods require the observance of specific formalities, such as obtaining the necessary witnesses and signatures. Colorado law mandates that wills and codicils must be executed in accordance with the statutes found in the Colorado Probate Code. When a new will is executed, it is advisable for the testator to destroy any previous versions to prevent confusion and ensure that the most recent will is recognized as the true expression of their intentions during the probate process.