What is the test for making an amendment to a motion?

The law on amendments is well set out in Klassen v. Beausoleil 2019 ONCA 407. The court affirmed that an amendment will be statute-barred if it seeks to assert a new cause of action after the expiry of the applicable limitation period. It further notes that an amendment does not assert a new cause of action if “the original pleading contains all the facts necessary to support the amendments [such that] the amendments simply claim additional forms of relief, or clarify the relief sought, based on the same facts as originally pleaded. [Conversely] an amendment will be refused when it seeks to advance, after the expiry of a limitation period, a fundamentally different claim based on facts not originally pleaded.” (paragraph 28).