Switching the sublanguage from EN (UK) to EN (US) for a defined group of terms

During data migration to a new termbase, some  200 terms were accidently imported into UK English instead of US English. I can filter those entries. Is there any way to switch the sublanguage for all those entries from UK English to US English without manually copying them from one sublanguage to anbother? I already tried to export the entire termbase and import it into a new termbase not contining UK-English (setting: ignore sublanguages), but it did not work.

Many thanks in advance for your suggestions.