We are currently running two instances of Marketo. I have built programs in the new instance that in need to import into the old instance, however, when I select import program in the old instance, it does not give me the option to import programs from the old instance.
You have to request support to connect between the instance. Once the support connects two instance you could see it on the import program button dropdown .
Note that connection is NOT bi directional. If you want to import from New to Old. Your request should be connect my Old instance to New.