Order In Counsel it is what is needed to change an FRT among other things.
Who says? The FRT is constantly being amended, updated and changed by the RCMP/CFC. There is no need for any OIC to do that.
Let's take a hypothetical situation...
A new (never before imported to Canada firearm) is submitted to the CFC/FRT Section for classification. The importer has a verifier submit the new import registration form and asks for a new FRT to be created. The gun is described as a non-restricted firearm and supporting documentation from the manufacturer supports that conclusion. In many cases no sample is submitted to CFC/FRT Section for inspection.
Based on the various documentation and materials the CFC/FRT Section issues an FRT # and classification of Non-Restricted firearm.
Now sometime later the FRT Section for whatever reason decides to review that previous classification and in it's 'wisdom' decides that an 'error' has been made and that the correct classification of said firearm is in fact 'Prohibited'. The reason for this amended classification is the contention that the gun was not as previously described. This could be because it is now felt the receiver was not a semi-auto receiver (as originally stated by the manufacturer) but that it is instead a modified version of a full-auto receiver and thus by Canadian standards it's a "converted-auto". If in fact it is a converted-auto then it should have been classified as a "Prohibited Firearm" from the start and this error is now being corrected.
Such a decision by the FRT Section would be their interpretation... they have the authority, based on that interpretation, to amend the FRT accordingly and at the very least to put that particular FRT # "on hold" pending the outcome of their review.
In order to overturn their interpretation one would have to get a court to overturn their decision and that's a much harder task than at first glance would seem to be the case. It is also a lengthly and costly procedure.
If the court agrees... then the change to the FRT is confirmed. If it never gets to court then the change to the FRT still stands... no OIC is ever needed. In any case it could take years of court fights to reach a conclusion and in the meantime the FRT # is held pending the final court ruling. All transfers are held in limbo... nothing can be imported... everything is effectively on hold.
Look at the G22... to this day it's never been 'ruled on' by a court. There are still guns here in Canada that are 'stuck in limbo'.