How to map utterances to intent

I am working on Alexa Skill invocation API

http://ift.tt/2zRpTf4

but this API takes intent as input but I have utterances so how can I map to particular intent intelligently while in testing in amazon alexa portal it gets input utterances and map itself to any particular intent but how can we do it in my side. I need to develop alexa testing on my site but unable to map utterance to intent. is there any Amazon API available which gets our utterance and give us intent name?