Amending returns

An amended return cannot contain original slips.

If you have original slips that were not filed with your return, file them with a separate original return. When you submit amended slips, please do not include slips that have no changes.

There are several ways to amend your return (cancelling or amending slips) after you have filed.

• Internet file transfer (XML)
  If you use payroll, commercial, or in-house developed software to manage your business, you can submit files of up to 150 MB over the Internet. See Amending returns - Internet file transfer.
• Web Forms
  You can file 1 to 100 amended slips using Web Forms. See Amending Returns Using the Web Forms.
• T4 Desktop application
  You can file 1 to 70 amended T4 slips using the T4 Desktop application. See Amending a return using the T4 Desktop application
• T1204 Desktop application
  You can file 1 to 5,000 amended T1204 slips using the T1204 Desktop application. If you file more than 5,000 slips, you must file your return electronically by using the Internet File Transfer (XML) application. See Amending Returns T1204 Desktop.