How to disconnect Zoho CRM from Zoho Invoice

How to disconnect Zoho CRM from Zoho Invoice

Hi,

I am testing Zoho applications and have connected Zoho CRM to Zoho Invoice. When I tried to connect Zoho CRm to Zoho Books I've got a message saying that this account (my email address) already exists. How do I disconnect/deactivate Zoho CRM from Zoho Invoice?

Thanks,
Stef