An invocation name is the name your users will reference when they want to learn more about your business (or invoke your skill). For example, if your invocation name is Mountain Town Airport, your users would say, "Alexa, launch Mountain Town Airport." - think of it as your domain name, but for voice.
Can you change it? Once your skill has been published with the platforms, the answer is no, it cannot be changed. The only way to change your invocation name is to create a new organization and start the process over again. If you wish to delete your existing organization and create a new one, the process should be done in this order...
1. Delete existing organization (see instructions HERE)
2. Create new organization (see onboarding instructions HERE)