How To Edit Captions in Screencast-O-Matic
First off, when you're in "Editing" mode on the desired recording, click on "Captions" and then on the "pencil" icon next to that:
You should then see a screen with the previous captions you've saved. Click on whatever section(s) you need to edit, when done click "Ok", then click "Done".
Then, choose "Upload to Screencast-O-Matic:
Once that's done, you will more than likely want to delete the previous video you uploaded from your account:
That should do it!