(1) If a party does not amend a defence or reply when entitled to do so under rules 16.55 or 16.56, the party's existing defence or reply operates as a pleading in answer to the other party's amended pleading.
(2) Rule 16.11 does not apply to the pleadings but, if no further pleading between the parties is filed, there is taken to be, at the close of pleadings, an implied joinder of issue in relation to the second pleading.