Under Florida law, a Last Will & Testament can be changed, but this must be done correctly or the court will not uphold the validity of your will.  Never make changes by hand or simply cross out items.  The only way to properly make changes to an existing will is to execute a codicil to the will.  A codicil is an amendment that attaches to the will.  Your other option is to revoke the entire will and start over.   

According to the Florida Statutes, the revocation of a will can occur in three ways: revocation by writing, revocation by physical act, and revocation by operation of law.  So if you want to revoke a will, destroy it and any copies, or make a new one that revokes all earlier wills.  Then in your new will you can be sure to add your burial and funeral arrangements, include new family members, or makes any other changes you would like.  Wills are dated when executed, so there will be no question about which came first.  For further reference, see Florida Statutes Section 732.505 on revocation by writing.  If you live in Florida, contact a Florida estate planning attorney for help with preparing a codicil or a new will.