If you take a look at your store, you will notice a small "Edit" button on the vids you have uploaded.
This is a handy tool that takes you back into the vid's edit page so you can make necessary changes like: adjust the price, replace the vid, change the vid preview or thumbnail, change your co-performer declaration etc.
Note: When editing previously uploaded vids, you will be prompted to make a selection in the Co-performer declaration area, and add any co-performer documentation before changes can be saved.
For detailed instructions on how to edit your vids, please click here!