Fusion Field Service - Technician / User deactivation steps

Summary:

We are unable to deactivate a user in Fusion Field Service which is already made inactive from Fusion.

Content (please ensure you mask any confidential information):

We are currently using the Fusion Field Service, and created / synced the users from fusion to FFS by providing the resource role field service mobile worker. However, We are facing an issue to in regards on how to remove a field technician or to deactivate a field technician in Fusion field service (Field technician) synced from fusion users.

Business use case 
Field Service technician has resigned and left the job. Need to make the field technician user inactive in FFS / Fusion.