GMCS doubts??

Hello freinds..i m supposed to sit in CAmpus Placement this August 2011from Banglore and i had applied for GMCS classes in KOLKATA ,i wana know that when i'l be in BANGLORE for campus from 14 - 20 august n i get a call from KOLKATA to attend GMCS then wat shall i do??i asked chapter office,they said to refuse and apply for the next batch again on returning..but i dont know how to Apply for the 2nd time as i think tht again i wud not got a call from institute after refusing  the first call???please tell can i refuse n how to apply again,