How to combine two similar termbases with duplicates only appearing once?

Dear Multiterm experts,

I have created a new termbase with a new field that says "approved", indicating all the terms were sent by the client, not the terms I entered on the fly within Studio Editor.

Now, I would like to import this new termbase to my existing bigger termbase that contains both the approved terms and draft terms.  I would like the terms from this new termbase to replace the same terms in the existing termbase, because the new termbase has the status information.  I tried the export and import approach with the new termbase, but found that the same term would appear twice, one with the additional field info and one without.  How do I make duplicated only appear once?

Thank you for reading my awkward explanation and many thanks in advance for your suggestions.

Chunyi