Hello Shabin,

Thank you for your interest in our product.

Amelia has integration with Google and Outlook Calendar. We don't have an integration for Crestraone, but please add a suggestion and to search through our feature suggestion page, and see if someone may be already suggested this feature. If you can't see it, feel free to add your suggestion there, and it will be forwarded to our management for review.

After it's been reviewed it will be presented on the front page, for voting. Please note that it may take some time before your suggestion is brought up for voting since we receive quite a lot of suggestions on daily basis.

Approval system work in such a way that you can choose whether the appointments will be approved automatically or you will they be set to Pending, and afterwards approved by the admin, manager or employee. Please check the details about our users and roles here. 

Unfortunately, approving the appointment from the email is currently not possible, only from the back-end or from the employee panel.

You can create two services one that will last three hours and the second that will last for a full day. Also, you will create an employee and assign him to both of the services, so when someone books the whole day second services that offer three hours services will be unavailable.

If you have any further questions please don't hesitate to ask.