Currently you can't modify a skill that is under certification, in general there are three statuses:
- Development: The skill is available only to you. If you have enabled it for testing, you can test it on devices registered to your developer account.
- Certification: Amazon is currently reviewing the skill for publication. During this time, you cannot edit the configuration.
- Live: The skill has been published and is available to users. You cannot edit the configuration for live skills. To start development on an updated version, make your changes on the development version instead.
Once your skill is published to end users (Live status), your skill’s status changes to live. You cannot change the configuration for a live skill. A new development version is automatically created in the developer portal. This version has the same information as the original live version, you can use this new version to continue to work on your skill to improve it and add features.
Taken from the Amazon Alexa documentation.