DEPENDS ON YOUR NATIONALITY ,HAH! DISCRIMINATION IS STILL...ANYWHERE! ANYWAY I SUGGEST JOIN WITH THAT COMPANY WHO  ALREADY SENT YOU A VISA.TOO LATE FOR YOU TO MAKE A CHOICE,DUDE.I GUESS YOU WERE GIVEN THE DETAILS BEFORE THEY GOT YOU A VISA,HONOR YOUR WORD AND COMMITMENT. THAT'S HOW IT GOES SOMETIMES.DEAL WITH IT.DONT TRY TO ENTER DOHA THEN EXIT TO CHANGE COMPANY AND VISA,BECAUSE I'M SURE THE FIRST COMPANY WILL MAKE IT DIFFICULT FOR YOU...YOU ARE GOING TO QATAR,DUDE.NOT SAME AS YOUR OWN COUNTRY WHEREVER YOU CAME FROM!