S4 Q&A: How do I request my SEVIS release?
You ask your current school's DSO, usually through their transfer-out form, giving the new school's details (from its transfer-in form) and the release date your consultant has confirmed with you. The DSO enters that date in SEVIS, and on that date your new school gains access to your record. Don't submit the request until your deposit is paid and your financial documents are accepted.