We are using the campaign option on Zoho CRM as an RSVP list for many of our events.

Many times we create a new campaign but want to use the same contacts as a different campaign, the problem is that we can't duplicate the contacts to the new campaign or transfer them. 

We tried exporting the campaign contact list to excel file and then import again, but any existing contacts aren't been added to the campaign.

Our basic need is to be able to import an excel file with existing contacts to a specific campaign. How can we do that?

Thank you for your help

Gili