They called and it was an on the spot interview. Once the interviewer saw that i could converse well, they asked me to complete 2 exams on the needed skill set. Sabre, Grammar, writing skill. Then there was a phone test as well. Those were not so difficult if you have customer service experience and the knowledge for the type of GDS they are looking for. Once you have passed they will email you, ask to send in/complete requirements and to choose the schedule you want to start.