Hi Elizabeth! We are glad you are here!
You can not re-import the file into WikiTree. You would end up creating duplicate files as you can not "update" profiles by importing new information. The reason for this is that each person is one leaf on the big, worldwide WikiTree. Other people have probably added their information to the profiles you want to update, so we want to be careful not to delete their research.
Anyway, that is the reason that you can't import update files without creating new duplicates that would each have to be merged back down to the original profile ID number. It would be a huge amount of work to merge those files.
Your best option at this point is to find each profile and add the sources manually. That way you do not create duplicate profiles. We strongly encourage you to add your sources and resources to the profiles. Thanks for your efforts and contributions to our WikiTree.