This excerpt taken from the ARW DEF 14A filed Apr 5, 2007.
Revocation of Proxies
The person giving the proxy may revoke it at any time prior to the time it is voted at the meeting by giving written notice to Arrows Secretary. If the proxy was given by telephone or through the internet, it may be revoked in the same manner. You may also revoke your proxy by attending the Annual Meeting and voting in person, though merely attending the Annual Meeting will not automatically revoke your proxy.