No point asking randoms on a forum this question, it's something you should be asking potential employers. In any case every large jet operator has a specific training and checking department/organization that inducts and trains all new pilots to whatever standard they require and in accordance with the regulations. Even if you had a current IPC or whatever from another airline on the 737 you would be required to go through an induction process for the new airline involving ground courses, sims and an IPC or equivalent. Get in contact with the 'HR priestess' and find out what you need to be eligible, they are the only ones that can let you know what you need, as it's probably different for each operator.