



There is no direct way to do the downgrade but you can follow the steps of copying the system databases of the enterprise edition instance to the instance of expressed one.Also making sure the new instance being the same with latest update to date with same patch details. In addition its better to go through Supported Version and Edition Upgrades while you consider to change the edition and compare features. In case the database is using any of such enterprise features, you will need to thoroughly verify, but not sure if express can get you there and most probably downgrade wont be that easy. The very first thing you would need to check on that instance would be for all the databases hosted, using any enterprise features from sys.dm_db_persisted_sku_features.
