Allow "until 7 PM" for AMAZON.DURATION slot
Let the AMAZON.DURATION slot process indirect durations from offsets of the current time.
For example, it is currently 2 PM and I elicit an AMAZON.DURATION slot from a user with a prompt like "How long would you like to stay?"
Most users will respond with a duration like "4 hours" or "30 minutes", but we've done some testing and some users would respond with an offset like "until 7 PM".
Could Alexa provide a match for AMAZON.DURATION slot with a value of "PT5H" in this scenario, because 7 PM is 5 hours from now (2PM)?
If you use an AMAZON.TIME slot to parse the response, Alexa will just give "19:00", and also you will lose ability to parse response as a formatted duration for most users who say "30 minutes" or "4 hours".