Switching a credit's department? aka from VFX to Anim?

Hi, I have several film credit's under the Visual Effects Department heading. I would like to move them to under the Animation Department heading as it's more appropriate. Consolidate the departments. I could not find a way to do this. I tried deleting the credits and adding them to the different department but it wouldn't let me move forward with removing them first. Thank you for any help that can be provided.