I cannot find front end way to add a new Change Window Type, currently have OOB Maintenance and Blackout.
Release : 17.2
Component : SERVICE DESK MANAGER
Out of the box there isn't a way to add a window type to the environment.
It may be possible to create one through a database load, but such a method would not be supported.
Adding Change Types - https://ca-broadcom.wolkenservicedesk.com/external/article?articleId=24224