When copying an existing CR it is not possible to change the status of the copy back to "New".
When a CR is copied, the new CR will have the current state of the original CR, including the same status. The only way the copy can obtain a status of "New" will be if the original CR workflow has a status of "New".
The only way to achieve this is to use a custom workflow in which the value "New" exists within each workflow step. If a CR is copied at some stage in the workflow it would then be possible to reset the value to "New".
Please review the StarTeam Extensions Documentation supplied with your StarTeam product for more information on using custom Workflows.
A StarTeam Enterprise Advantage license is required to use custom workflows with StarTeam Extensions.