Hi, I am a postdoc and going to file I-140 under NIW by myself, my questions are: 1) Is that OK if I have my supervisor (not the university) write the cover letter for me in a manner such as "I am supervisor of Dr. XXX, for such such reason, I respectly request you approve Dr. xxx's petition" while I do everything else by myself? 2). If it is OK, do you think I still have the freedom to change the employer during the processing(just like a regular self-petition NIWer)? Because this realy makes me confuse, hopefully I can get some suggestions here. If anyone can give me the suggestion, it would be great appreciated. Thanks.