It is always recommended to create and test your custom reports in your testing environment before you put them into the productions system. Once your report is working and showing the correct data, you can migrate it to the production site by downloading the reporting page from the source site and uploading it into the destination site. Downloading a Custom reporting page is also good way to back up your custom reports or create a copy of a reporting page.
Note that your source and destination sites must be using the same or a very similar version (only 1-2 releases apart) of the FAST software.
Downloading a Custom Reporting Page
Uploading a Custom Reporting Page
Once you have uploaded the new Custom Reporting Page, you will have to go into the Manage Reporting Pages and approve the report before it can be used.
This process will not bring the roles that are assigned to the report into the new environment, so you will have to assign the roles for the new report to it after you have imported the pages.
Assigning Roles to a New Custom Reporting Page