You can use the Collection Manager to change the content model for all objects in a collection that use that model. This allows you to, for example, upgrade all the audio files in a collection from an existing Islandora content model to a new Solution Pack version of the content model.
1. Navigate to a collection and open the Collection Manager.
Choose a collection and click the 'Manage This Collection' tab at the top.
2. Change the content model for all related collection objects.
Expand the 'Change Content Models' section and choose a content model to be changed. Then choose the new content model to replace it.
Click 'Change Content Model Associations' to complete the operation.
You have successfully changed the content models of all related objects in the collection.