Please see the ministry website link below regarding documentation required.

http://www.gov.qa/wps/portal?New_WCM_Context=/wps/wcm/connect/cnt/EN/1_H...

However you need to complete one year to change profession. Also certificates to be translated locally and originals has to be attesetd by Qatar Foreign affairs. I am suffering from the same! Believe me it is NOT SIMPLE.

AJAY