First, you have to remove the file from the protocol step where it was originally added and then upload it again to desired protocol step. To do this follow these steps:
Click the Edit icon.
Click the File tab, select a file that you want to remove and click X. Click Save to save changes.
To upload a file to another protocol step, click the File tab again and click Browse to add or drag and drop multiple files.
Choose a file from your computer and click Save.