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 and click Cancel
A pop up will appear, select cancel visit and enter the reason for cancellation and any additional notes
Select the billing time for that visit and if the visit should be paid to the carer (carers)
The cancelled visit will turn grey, you can un-cancel it by clicking on the visit again.
Cancelling on Schedule Page
Open the schedule page.
Click on the visit you wish to cancel and click Cancel
A pop up will appear, select cancel visit and enter the reason for cancellation and any additional notes
Select the billing time for that visit and if the visit should be paid to the carer (carers)
You can un-cancel it by clicking on the visit box again.
Visit List Report-Invoicing purposes
To see cancellation reasons in your invoice reports you just need to tick the box for cancellation notes in the 'Settings' menu in Reports.
If a cancelled visit has a billed time = 0, it won't appear in the invoice, so make sure that cancelled visits have the correct billed time before to create invoices (in the Visit List report you can filter to see only cancelled visits and go through that list)
Cancelled Visits in Payroll
If you selected to paid the planned time for a cancelled visit to the carer or carers assigned to that visit, the cancelled visit will appear in the Payroll report with the Paid time being added up in the Total Pay
Cancellation Reasons
If you have an Admin role, you can set what cancellation reasons to be visible in the cancellation reason list, you can also define which cancellation reasons by default will be visible in the Payroll with planned time. To learn more about Cancellation Reasons and how these are integrated in Payroll check this article