TLDR: For the comprehensive income tax return, correct the information entered in the previous return, then sign it again. Make this correction within the additional deadlines applicable.
Correcting an income tax return
After signing a comprehensive income tax return, you can correct the information entered in the previous return, then sign it again.
This procedure concerns the comprehensive income tax return. It does not constitute a general rule applicable to all returns submitted via EFI.
Complying with the correction deadlines
Make the correction within the additional deadlines applicable to the income tax return.
Do not confuse EFI and EDI
The rule according to which a new submission cancels and replaces the previous one until the “Substitution Deadline” concerns the EDI channel.
For the income tax return referred to here, the correction consists of modifying the information in the previous return, then signing it again within the applicable additional deadlines.