In finding that a subsequently-filed letter request was a valid late designation under s. 104(13.1), Archambault J stated (at paras. 25, 26):
[A]lthough there is no general provision in the Act authorizing Canadian taxpayers to amend tax returns already filed, there is nothing to prevent them from doing so…[and] it is in the interest of tax administration to allow such amendments. …
…[T]he letter…was an amendment to the estate's tax return and its effect was to amend the initial return.