It would be possible Slot was created in-session? i.e, I would like to build a slot depending on an API Rest response. Alexa prompts to user the values of this slot an it would choose one.
You can try using dynamic entities in this case. Just be aware that they might not work perfectly, so try them out and see for yourself. But overall, what they allow is to add slot values dynamic in every response. So when you want to add new values, add that directive with new slot values and it should work.
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