How to edit a Roku channel created by someone else

Our church Roku channel was developed by a streaming provider that we are going to drop. We have a Developer account showing the app published by the previous streaming company. We need to make the changes to the account for new media as well as live streams. Any help as far as what we may need to get this going would be greatly appreciated. It may be something easier than we have found just need to be pointed in the right direction and is there a program we need to use for this.