Change roles of sign-offs
You can change the sign-off owner role or sign-off reviewer role of a sign-off only if the sign-off status is Open and the review status is Unspecified. The auditor role can be changed independently of the object status.
Prerequisites
The change of roles assigned to tasks is enabled in Risk and Compliance configuration of ARIS Administration (General workflow).
You have the Sign-off manager role.
To change an assignment, open the respective object and click 
Assign or 
Remove under Roles responsible in the row of the relevant role.