Open the file using the menu option file->open make the changes and recompile the report.
Convert the file into .REP file using the report compiler make the changes and convert the file back to a .REX file.
Execute the R30CONV command to convert the file to a .RDF file, make the changes and convert the file back to a .REX file.
Choose file -> administration->compile. Convert the file to a .REP file, make the changes and convert the file back to a .REX file.
Execute the R30CONV command to convert the file to a .REP file, make the changes and convert the file back to a .REX file.