AAD device enroll to intune

Folks, I just start this new firm. All Windows 10 devices are connected with AAD (there is no on premise AD or DC). Previously, IT department connecting devices to AAD with one specific Userid. So about 600 devices ownership are relate with this specific id. I would like to enroll to Intune, but since they are registered with one unique id, not able to publish anything. 

I know I can have user disconnect and reconnect to AAD, but there are too many computers. When you disconnect it, it ask for local admin password, restart, login to local admin and reconnect with user id. So, it seems like it wouldn't be good idea for user doing these all. Is there way to auto enroll all devices regardless who is ownership of that device. looking for some help ...

thanks