Actually. You can't just rename it.
You would need to configure another box and set it up or redo the current box.
Using another Server, you need: (for single Domain Controller using Active Directory)
Rename the sole DC in your domain, and preserve Active Directory information that
you've configured, using Dcpromo.exe or the Configure Your Server Wizard.
1. Use the Active Directory Sites and Services Microsoft Management Console (MMC) to
force replication.
2. Make this new domain controller a Global Catalog server.
3. Transfer, NOT seize, all the FSMO roles, that the original domain controller holds,
to the new DC.
4. Use Dcpromo.exe, or the Configure Your Server Wizard, to demote the domain controller
that you wish to rename.
5. Rename the demoted server using Control Panel / System / Network Identification / Properties.
6. Use the Configure Your Server Wizard, or Dcpromo.exe, to promote the member server back to a
domain controller.
7. Reconfigure all the FSMO roles and Global Catalog.