If you realize that there are corrections to be made to claim that you have submitted, there is a window of time that the claim submission can be returned to Unsubmitted.
For that, find the health input file in File Centre > EDT Files. Click the three blue dots and then select Undo File Submission. If possible, it will put those claims back in your unsubmitted claims where you can make the correction and submit them all again.
If the claim is already uploaded, there's not much we can do until the claim is either rejected or paid. If the claim is rejected then you can easily make corrections and resubmit. If the claim is paid, then you would need to submit a "Remittance Advice Inquiry (RAI)" form to make the correction.