You want to amend a return using TrustFile.
At this time, TrustFile cannot be used to file an amended filing.
TrustFile can be used to complete delinquent filings up to the end of the month, when the return is due, but since your data is always filed for the current filing term, it is not possible to go back to a previous term to amend a filing.
Amending returns through TrustFile will likely be available in the near future, to support both of those scenarios.
To amend a return, you will need to coordinate with the state's Department of Revenue directly.