12:00 am ET might be unsuitable for CT time zone
When planning a call between Eastern Time and Central Time, you need to consider time difference between these time zones. ET is 1 hour ahead of CT.
It is 12:00 am in ET. This does not fall within the span of usual working time between 9:00 am and 5:00 pm in CT, but it still might be suitable to arrange a meeting, since it would be 11:00 pm in CT, which is between 7:00 am and 11:00 pm CT time.