Upgrading SQL 2005 Evaluation to Enterprise Edition Without Uninstalling

Can we upgrade SQL 2005 Evaluation edition to SQL 2005 Enterprise edition without uninstalling the evaluation edition? This seems to be lingering in the minds of many DBA and hence I thought of explaining it in simple terms. Yes it is possible to perform the operation without uninstalling Trial edition of SQL 2005 prior to the end of the 180-day period.