We are developing a lead intake form for use at tradeshow events.  Purpose is to collect new lead information and integrate with Zoho CRM.  In our CRM the email field is unique in all modules.  Our form is integrated with the leads module in CRM.  As I am testing the form, I notice if an email of a Contact is entered, rather than updating the Contact record, it simply fails.  For most companies, I would think this is an issue.  The people we meet with at tradeshows are a mix of new leads and existing contacts.  Is there really no way to manage this using a single form?