I worked for a large company in Chicago (~$40B sales) which purchased another si

I worked for a large company in Chicago (~$40B sales) which purchased another sizable company (~$15B sales) in Detroit. Both companies had large corporate offices. The risk assessment was to determine if we should maintain two company headquarters offices. Identifying the risk was not the issue. The issue was to evaluate the pros and cons of having two corporate offices.
How do you think we mitigated the risk?