Step 1:

Inside the transaction, go to the documents tab and click the file name that you want to edit.

Step 2:

The right-side panel will pop up and hover over the Name field box to edit the file name.

Step 3:

After adding the replacement name, click the check button to save the new file name.

Instead of manually typing the replacement file name, you can click the File Role dropdown and choose which file role name you want to use as a new file name. Choosing a "File Role" will override the current document "File Name"