The property exists only in this version: Delete the PageList property rule and create a new one with the same name, but different type definition
The property exists in an older version (e.g. RuleSet:01-02-03) of the RuleSet: Do a save-as of the property rule in the 2nd highest open version (RuleSet:01-02-04) and set the availability to withdrawn (= delete). Then add a new property rule in the highest version (e.g. RuleSet:01-02-05) and specifiy the new type definition.
Maybe there is a more convenient solution for scenario 2.