Move selected OU from On-Prem AD to cloud only AD

Hi .

We have On-Prem AD sync with azure for O365 . 

Some of OU users are Remote users and so they are not connected to AD. We have business basics license so reset password of mail id from Cloud is not possible due to license limitation. 

So we are thinking of moving those users to cloud only so they can reset their password.

Is there any safe way to migrate them to cloud only?