Many clauses in commercial leases are “permissive”, and let the tenant implement changes to the property or its occupation (for example alienation or user). Usually, however, the landlord’s formal consent is needed, and the lease will contain provisions governing how this is to be retrieved and documented. These clauses also usually provide for the landlord’s approval not to be unreasonably withheld or delayed and, if not, provisos to this effect are imported by statute in relation to alterations and alienation, but not user.