Guest check-out related settings can be found under Settings -> Guest Account

• Enable Online Guest Check-out
  When enabled, the system will email guest in the morning of the check-out date, prompting to start the online check-out process
• Offer Late Check-out options during check-out
  When enabled, the system will provide Late Check-out (LCO) Time options during Guest Check-out. You will also need to setup the Late Check-out options under Setup >> Early Check-in / Late Check-out.
• Min Availability when stop selling Late Check-out
  Set minimum availability for each inventory product – System will stop selling LCO if the availability is lower than this limit