The following information is supplied from the website GuestDiary.com (www.guestdiary.com)

Promotion Codes

AccuBook GuestDiary have now released the Promotion Codes module in our PMS.
Promo codes provide a quick and easy method to offer discounts or free extras to your guests. The following article will introduce you to promo codes, and provide you with a step-by-step guide on how to use them.

Promotion Codes
How will my guests use promo codes?
When someone is looking to book through your booking engine, they have the option to enter a promo code before they carry out a search. If the code they enter is valid, the message you provided with the promo code will be shown, and the promo code will be applied to all occupancies that are associated with it.
Search results affected by the promo code will be sorted towards the top and will be marked with a label indicating that the promo has been applied.
Can I send a link to a guest with the promo code?
Yes, you can! If you are familiar with the special offers link builder, it is the same process. On the promo codes page (i.e. where you can view your existing promo codes), you will see an orange button labelled Generate Promo Link. Hit this button, and a popup will be displayed.