If a client has booked in for a colour and finish but you then decide they need a treatment or a toner then you can adjust the bill easily so when you check out it is all correct.
To make changes to a booking, simply click anywhere on the appointment to surface the modal. Click the 3 dots top right and select edit booking:
This will open the booking window where you can add or remove any services you like
Treatments or toners can be dragged to overlap the colour appointment if you want to conserve space in the calendar:
Long term Slick will be introducing a 'pre-checkout' feature which will allow you to add services & retail products to a bill in advance of checkout so watch this space