If you are within the date on your I20 and no more than 6 months have elapsed on your visa. You would then ask your school to transfer you to your new school. They cannot refuse to do this.
Remember that it is NOT the date on your visa. It's the dates on your I20 which count and if you have completed the training or exceeded those date then your visa is not valid and you would need a new one even if attending the same school.