(1)  Subject to any order made under rule 427(1) , if a party amends a pleading under rule 427(4) , rule 428 , 429 or rule 430 the opposite party is to plead to the amended pleading or amend its own pleading to meet the amended pleading within the later of –

(a) the period the opposite party then has to plead; or

(b) 8 days after the delivery of the amended pleading.

(2)  If a party pleads before the delivery of an amendment and does not plead or amend as required by subrule (1) , that party is taken to rely on the original pleading in answer to the amendment.