In EFT subscription licensing is only available in version 8.0.7 and up. 

To change the license in EFT you will need to:

Open the EFT Admin Interface

Click help 

Click into the licenses and click manage 

You then need to remove all licenses from bottom to top, ensuring the last license removed is the main EFT license 

Once all are removed, add the new licenses in with the main EFT license added first.