If you need to make edits to a live Alexa Skill, but that skill is not linked to a current Voiceflow project, you can re-build the skill in Voiceflow and manually update the Amazon Skill ID associated to it.
To start, open your project in Voiceflow.
The next step is to copy your skill's URL and change the word "canvas" to "migrate"
You'll then see this page:
Now, you can enter your Amazon Skill ID, and voila! Your existing Voiceflow project is now linked to your live Amazon Skill.
Need help finding your Skill ID?
After uploading your project to the Alexa Developer Console (ADC), under the name of your skill, there's a button that says View Skill ID.
The skill ID is quite long and looks like this: