Explanation
Configuring the new app in a sandbox and using a change-set to push the configuration to production for testing and training is a recommended way to mitigate the concerns of disrupting current operations and impacting customer satisfaction. A sandbox is a copy of the production environment that can be used for development, testing, or training purposes without affecting the live data or users. A change-set is a collection of metadata components that can be deployed from one Salesforce org to another. By using these tools, Universal Containers can ensure that the new app is working as expected and that the agents are familiar with it before making it available in production. Verified References: Service Cloud Consultant Certification Guide
& Tips, Sandbox Overview, Change Sets Overview