Change of Degree Program
You must also apply for a new Form I-20 or DS-2019 if you continue at our school in a different academic program, for example, if you have been accepted to pursue graduate studies (Th.M. or Ph.D.) after completing the M.Div. or M.T.S. program.
Please note that the above applies to you even if the F-1 or J-1 visa stamp in your passport placed there by a U.S. consular officer has a limit of, say, one year. This stamp need not be renewed because it covers entry into the U.S., not the legality of your present status.
The only time this visa stamp must be re issued is when it has expired, you leave the U.S. for a temporary absence, and you wish to re enter to complete your studies.