Our CAB has 300 members. This includes executive directors for the various IT portfolios and Service Owners and their delegates. It also includes many of the support group areas. If there are questions about the change that cannot be answered before or during the CAB meetings changes are conditionally approved until those issues/questions are resolved. That may result in changes having their implementations delayed. Those people who submit changes for review in a particular week also attend cab along with any SMEs they need to present their changes.
If a change goes unchallenged and has no issues during the meeting the change manager (within the ITSM group) moves the change to the next stage so that the final approval tasks can be fired.
I'm the director not the practice owner so I may get the next part wrong a little bit. Leaders from applications upstream or downstream either get a notification or an approval. Leaders for the CI in question definitely get an approval, and technical support areas who will be working on the change get an approval (before it comes to cab I think).
Keeping in mind only changes with significant risk come to the cab meeting itself.
Coordinating dates and gathering approvals from business stakeholders is the job of the change owner.
CAB is generally one hour a week.
