Sometimes it is useful to create a report model that can be used against multiple databases that have the same structure, but reside on different servers and/or have different schema qualifiers.
Uploading a second copy of a report model and pointing it at a different database is certainly easy enough, but you can run into issues if the second database has different schema qualifiers. The problem is that, by default, the Data Source View wizard creates a DSV that includes schema qualifiers in the bindings. If those qualifiers are not necessary (i.e. the bindings can be fully resolved if a default database is specified in your data source connection string), you can make your report model work for the second database by opening the .dsv file in a text editor and use Find/Replace to simply remove all the schema qualifiers.
Test it out against the old and new databases, and you should be good to go.