You would require to modify the record rules for it. When you mean manager do you refer to employee's manger as defined in Employees App or do you refer to team leader defined on the sales team?

The below is for employee's manager in Employee (HR) App

['|','|',('user_id','=',user.id),('user_id.employee_ids.parent_id.user_id', '=', user.id),('user_id','=',False)]