Hi SHAN CHAN 

you can edit existing termbase definitions, but only by adding new data categories (fields). You cannot remove or rename data categories from existing termbase definitions in MultiTerm. If the latter is the sceanario you need to tackle, there would be two possible workarounds:
1. Save your termbase definition (as XDT) and make the changes to the XDT file in an XML editor and then load the XDT.
2. Export your termbase make the corresponding changes to your exported termbase in an external editor according to the needs in your new termase, set up a new termbase, and import the edited export file.

Best wishes
Detlef

Hi SHAN CHAN 

I think Detlef was just explaining how to handle all kinds of changes. If the changes you want to make are to add new fields then it's no problem, just add them in termbase management. But if you want to remove or rename existing fields then the only way to handle this is to export to a multiterm XML and XDT (the termbase deifinition file). Then create a new termbase using your XDT so the definition is the same, and remove or rename any fields you like. Then import the XML.

The easiest way to do all of this is using the Glossary Converter from the appstore because it can handle the export/import in a far easier way.