A customer requested to change one of the user's profile and role of the company from 'Salesperson' to 'Head of Sales'. And so I did. The user can now access some more modules and actions and follow some opportunities of their now subordinates.

Problem is, the customer requested as well that all these users who are 'Head of Sales' to no longer have access to the opportunities they created when their profile/role were 'Salesperson'. 

I suggested to move ownsership of those records but no joy there. There is a need to keep Opportunities History with the right owner. Is there any workaround possible? Well, I believe it's not possible to hide records created by any user from themselves even when the role is changed, right?