Yes. There are no restrictions to change the module from Accounts to Accounts and their Contacts and vice versa. However, if you want to change the sync type from Contacts Only to Accounts or Account and their Contacts and vice versa, you will need assistance from us.
For instance, if you wish to change the sync type (Between Zoho Books - Zoho CRM) from Account and their Contacts to Contacts only, we can help you set up the sync in two ways depending upon your preference:
OR
Write back to us at support@zohobooks.com mentioning your preference and we will do the necessary changes from our end to set up the sync.
Books
Simplify accounting
and GST filing.