How do I clear a received email's display name in a Blackberry Curve's cache?

One of our users has a Blackberry Curve. He received an email from a new outside vendor a few weeks ago. The vendor had the wrong display name configured in their email and has since changed it, email address has stayed the same.

The problem is that everytime my user receives an email on his Blackberry from the vendor it stills shows up as coming from the old display name. However, when he goes into Outlook on his laptop the new, correct name is displayed. I am guessing this has to do with the Blackberry's cache.

Anyone know how to get this vendor's display name to show up with the corrected name on the Blackberry?

Thanks in advance.