Jordo's Playbook: Changing Email in CRM
The Situation: A salesperson discovers that the primary email address for a lead/contact has changed. He/She changes the email address in the CRM system to reflect the new primary email for that lead/contact. Since Eloqua auto synchs use email address as the unique identifier, the auto-synch will run and try to find a match using the new email address. However, since this change has only been made in the CRM, it will not find a match in Eloqua and therefore create a duplicate record. Needless to say, this is far from ideal!
The Solution: Create an autosynch that references the Lead / Contact's history object in Salesforce.com. Use the old email address value as the unique identifier to match Eloqua's database and use the new email address value to overwrite it once a match has been made (don't worry.....if your confused, just follow the Play by Play!).