What is the difference between a Modification (M) and Error (E) for REMIT reporting?
A modification can only be used when the bilateral terms of the trade have changed and both parties involved in the trade should send a modified submission.
An error should be sent when there is a mistake is in the submission that needs correcting. You should follow the steps detailed in Section 8.3.3 of the CMS User Guide, found on the CMS Welcome Page.
Modifications should not be used to correct mistakes.