For example, we could have a process that contained the following sequence of
tasks:
record ticket booking;
issue tickets.
In this example, the stated sequence of tasks is not open to question but we could
consider why there are two separate tasks, and ask whether they could be carried
out at the same time. If we investigated what could prevent the issue of the tickets
and cause a task other than ‘issue tickets’ to be invoked, we might find that: