In the client's calendar If the visit is unassigned, you can modify all aspects of the visit. Including notes, number of carers, services or duration of the visit.
Just click on the visit in client’s calendar (people > clients > calendar)
The visit window will open, you can make modifications save
You can make edits to just one visit or all of them if they are in a repetition
If the Visit is Assigned
Open the visit on the visits page or on the client's calendar
The visit window will pop up allowing you to edit all aspects of the visit