In UML, operations can have preconditions defined, which are constraints that must be true before the operation is invoked. When an operation is redefined in a subclass, it is possible to add new preconditions or alter existing ones. Redefining an operation does not typically allow for changes to its scope or the addition of templates, but the preconditions may be expanded to reflect the semantics of the subclass. This is in line with the behavioral specification of operations in UML, where preconditions are part of the behavioral contract of an operation, as described in the UML 2.x Superstructure Specification.