Hi Jim,
Normally you would unload your data first using a tool such as the Tamino Data Loader or Java Loader, then undefine and redefine the schema, then reload the data. You might need an additional step to modify the unloaded xml data prior to reloading it, if the schema changes demand it.
In your case, where the data is completely lost, you could restore it first, and then start with the process above.
Does this help?
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