The Confirmation Node is used to detect affirmative or negative responses and the NL engine can detect over 100 different ways each of saying yes or no. However it may be that there is a special colloquialism or slang that is used in your business that is not part of the standard Kore platform.
The set of words that are detected as a yes or no can be extended by using special bot level synonyms.
For extending yes, use the keyword ~confirmation_yes and for no use ~confirmation_no.
e.g.
Keyword: ~confirmation_yes
Synonym words: I am done
Keyword: ~confirmation_no
Synonym words: go away