A codicil is an amendment to an existing Last Will and Testament

When a person executes a Will, he or she may amend or modify the Will at any time so long as the person is living and competent. This type of amendment is referred to by estate planning lawyers as a codicil. The codicil may amend by adding, revising or removing existing provisions. 

When executing a codicil, the same requirements that apply to a Will apply to the codicil. So in Florida, this means that the Will must be executed by the person in the presence of two witnesses and the witnesses must sign in the presence of each other. 

Although there is no limit on how many codicils a person may have, better practice suggests not having multiple codicils. Consider what would happen if a person had their original Will and three codicils and at the time of death one of the codicils cannot be located. In a case such as that, it would be more prudent to just do an updated Will incorporating all changes.