Hi Alex, please move this to Products (Move link at the right). This space is for questions about the Champs incentive program itself, not support (and yes, it's confusing because there are also blog posts here.)
Hi Alex Dreiling,
Check out this page Edit Initial Field Mappings - Marketo Docs - Product Documentation
I'm assuming you have your fields mapped to each other in SFDC so when a lead becomes a contact the value persists and is carried across.