Zoho integration of two zoho crm systems

Zoho integration of two zoho crm systems

we have 2 separate offices.. one as the head office and one as a form of franchise. Consequently 2 separate CRM systems are running similar data. We are now looking to integrate the complete data from the 'franchise' system to the head office system and all employees work from the one system. what is the easiest way to integrate the data into the main system without losing any notes etc?