Non immigrant visas extensions are extended as normal if you still meet the conditions of the extension.
However if they are expiring due to you not meeting requirements of it or you don’t meet the requirements anymore You can apply for the emergency extension as long as you get the letter from your embassy.
If you are on extensions you must cancel the extension first.
You can apply for an emergency visa after receiving paperwork from your embassy AND also cancelling any extensions if you don’t meet the requirements of the extension.