sm_user role for service mapping

Hi All 

there is an OOB role sm_user for service mapping . 

This role inherits itil role . Now as we are looking to replace itil with BS ( Business stakeholdder ) , we want to understand the impact if 

a. revoke sm_user role and give BS . Will users still be able to view service maps ? 

b.modify the roles inherited by sm_user and replace itil with BS 

For both of the above scenarios , will user still be able to access service maps .

please guide me , need urgent help 

regards 

GARY