You ought to appear for the interview
to get GC if your case is transferred to local office. I have come across no simple way,which will get you an approval in such a case w/o the interview.
RFE (request for further evidence) is call for submitting additional paper(s) as evidence to clear any doubts INS officer has about your eligibility.
Its purely his/her call to send an rfe or transfer case to local office, once he/she has a doubt.