Abstract: A user of a native system desires to work with a foreign file containing data in a foreign format. To do so, the foreign file in the foreign format is converted into native file a native format. Data in the foreign file that is not representable in the native format should be preserved. Translation of the data into the native format allows the data to be manipulated, edited, changed, etc. by the native system. Any alterations made to the data using the native system can be tracked, for example, by creating a list of changes. The foreign file can be updated to reflect these alterations by directly changing the foreign file, rather than by attempting to recreate the foreign file from the altered or edited native file.