If data is received for a tag with the same index (timestamp is often the index but check with your Data Architect to be sure for your case), the data received most recently overwrites the prior data. This functionality can be used to correct data sent on a prior form simply by resending the form with the same index.
If the time the form was submitted serves as the index, it would not be possible to resubmit a form with the same index. For more complex cases like this, please create a Todo for assistance. You will likely be asked to complete a csv file with the updated form data and upload that file to overwrite prior data.
Keep in mind that data with a timestamp older than your auto processing window will not process automatically. When older data is submitted please initiate your process for historical data processing via Todo.
Alternatively, consider using the filtering capabilities in the Braincube toolset to clean the data with your usage.
Also, consider ways to design your form to minimize errors.