But the purpose of a declaratory judgment in such a case is "to guide and protect [executors] from uncertainty and insecurity with respect to some future act or conduct." Hammond v. Sanders, 210 Ga.App. 307, 308 ( 436 SE2d 45) (1993). When the rights of the parties have already accrued and no uncertainty exists that requires the court's guidance, a declaratory judgment is not authorized.