Pass the ball back to 1st Party Alexa for a response
We keep the skill session open with users by giving them a follow up question prompt like "what else can I help with?". I have to believe there are a lot of skills that do this. There are quite a few circumstances where users ask things that 1st Party Alexa should respond to, not our skill. (Things like asking about the weather, about tides, or asking for a joke). We would like to be able to pass the ball back to 1st party for fulfillment.
This could be done by either closing the skill session and providing the 1st party response, or providing the 1st party response and while keeping the skill in session. The 2nd option would be preferrable, but if it is much easier to do the first option that would be a good place to start.

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Brian Tarbox commented
If a user asks a 1st party question such as "what is the weather" while inside a skill the system responds and then says "returning to skill xyz".
It would be great if more such 1st party requests were handled like this. There's no reason for my skill to get Fallbacks when someone says "increase volume" for example.