You can see the previous flight made by the same lion air plane that crashed here[1]. They not only did not declare an emergency but they contained the flight as normal and flew for over an hour with no MCAS and no electric trim.
[1]: https://leehamnews.com/wp-content/uploads/2018/11/Previous-f...
I should point out they found the stab cut out procedure by trial and error and were able to maintain control of the plane simply by counteracting the errant downward trim. The reason the Ethiopian plane crashed is that they didn't execute the airspeed disagree procedure and left the throttles on basically maximum.
Yes MCAS is an issue, But since no one on this site has gotten this right I might as well point that out
