It depends entirely on what encryption method you chose to use - simplest approach would be to copy the files off the stick, format it, and put the back.
If you're using file level EEFF though you will also need to give users permission to decrypt them (and either put them though a new decrypt policy, or right click - decrypt each file)
If you are using hardware encrypted sticks, there's no option to not use encryption.
I found the answer in archived docs:
Remove encryption on File or Folder with MEE
NOTE: It is recommended to Open the Removable Media with password, Copy all data to another location and then format the Disk. This is a McAfee recommendation. The below instructions do not always retain data following decryption.
- Insert Removable Media
- Input password to open encrypted Removable Media access
- Open Explorer
- Highlight Removable Media Drive Letter
- Right-Click, Choose McAfee Encryption icon from listed choices
- Choose remove encryption
- Note: you WILL be asked for the password to decrypt
- Note: You will be warned all data may be lost during decryption. (See initial warning)
- Wait, decryption will take time depending upon Removable media size.