You can only cancel visits in the future, you must use the reports section to edit any visits in the past.
Cancelling in Client Calendar
Open people > client > calendar.
Select the visit you want to cancel.
A pop up will appear, select cancel visit and enter the reason for cancellation.
The cancelled visit will turn grey, you can uncancel it by clicking on the visit again.
Cancelling on Schedule Page
Open the schedule page.
Click on the visit you wish to cancel.
Enter the reason for visit cancellation and click cancel visit.
You can uncancel it by clicking on the visit box again.
You can add a specific note to your cancelled visits to highlight that the they will be invoiced or not (for example if your policy is to charge for visits that have been cancelled with less than 24h of notice). To see cancellation reasons in your invoice reports you just need to tick the box in the 'Settings' menu in Reports.
In order to add the cancelled visits to your invoices, make sure the billed time is set the same as the planned duration.
