You can easily re-book your client for next time, without having to re-enter all their details again. Just go through the checkout process (see here for how to checkout a client: http://help.getslick.com/using-slick/how-to-checkout-a-client), and at the end you'll see the option to rebook - then just follow these easy steps:
After confirming payment, hit Rebook:
The booking window will open with your client's name and the services they've just had already pre-filled ready to book for next time.
The new booking with default for today at the same time as the appointment that has just been checked out, but don't worry, you can simply use the date picker to select the date your client would like to rebook and the booking will "follow" you to future dates:
Once you've arrived on the date your client would like to rebook, you can continue to edit the booking as normal and then just hit "Save Booking" to confirm the rebook!