Let say currently your report name is "Account_Summary" and the name of your view is "Account_Summary_View".
In this scenario, you have created a new view "Account_Detail_View" and now you want your existing report "Account_Summary" to start using this new view.
The best way to do this would be to export your report without the old view, then import it back into your repository - making sure to attach it to the new view during the importing process.