Since Calenso v4.25.0, every customer who books an appointment with Calenso has his or her own public page where he or she can view, rebook or cancel all past and future appointments.

Open customer page as partner

Go to the customer management, click on a customer name. On the top right you will find a button called "Open customer link". Click on it and the customer page will open:

Send link to customer page

Use the placeholder [CUSTOMER_LANDINGPAGE] in the templates, e.g. in the appointment confirmation to the customer.