For simply accounting 2011 or earlier:
The Pay Remittance feature does not have an Adjust or Reverse option in the journal; as a workaround you can try the following:
The above reverses the remittance payment you posted. The amounts, however, are not put back in the Pay Remittance journal. The amounts are updated in your account balances.
If the reversal was done to update the date or cheque number and the amounts were correct, you can create a brand new transaction through the Make Other Payment journal:
If the reversal was done because the amounts were incorrect, you still need to create a new entry for recording the remittance payment with the correct balances. You can create this new entry using the Make Other Payments option following the above steps or through the Pay Remittance journal.
Important: In this case, your remittance report will give you incorrect amounts at the end of the year. Make sure you verify this report carefully before submitting the information to Canada Revenue Agency (CRA).