12:00 am CST might be unsuitable for PST time zone
When planning a call between Central Standard Time and Pacific Standard Time, you need to consider time difference between these time zones. CST is 2 hours ahead of PST.
It is 12:00 am in CST. This does not fall within the span of usual working time between 9:00 am and 4:00 pm in PST, but it still might be suitable to arrange a meeting, since it would be 10:00 pm in PST, which is between 7:00 am and 11:00 pm PST time.