You will need a new EIN if any of the following are true

1. You are a subsidiary of a corporation and currently use the parent's corporate EIN
2. You become a subsidiary of a corporation
3. The corporation becomes a partnership of a sole proprietorship (It varies on each state)
4. You create a new corporation after a statutory merger
5. You receive a new corporate charter
6. The EIN will not be changed if you have changed the existing name of the company.
7. Changing a company structure such as corporation to an llc or vice versa