You woudl have to Export the data from one form and Import it into the other. You cannot automate this fully. You can add a button for export and import that woudl use these commands:
Export - xfa.host.exportData("", false);
Import - xfa.host.imortData();
You cannot automate this fully as you cannot supply a filename (the user must pick it) for security reasons. Note that because you are only dealing with data, Reader can be used without Reader Extending the form.
paul