green card cancellation

[chiooz]

hi,

i had a question here regarding the green card application. Is there anyway that an emplyer can put the green card application on hold and restart it as and when he wants it? I-140 stage where teh employer is about to put the employee name on it

And also, if the employer cancells the green card application accidentally? is there anyway to get it started goin where it left off? I-140 stage.

thanks