Change the name of node

There's no good way. Editing the bigip.conf file directly can cause issues down the road, and if you make a mistake you may have a config that won't load. I've been stuck at SOL13030: Forcing the mcpd process to reload the BIG-IP configuration more than once from editing and reloading bigip.conf

You can always go to the standby unit, remove the nodes from pools, change the names, and re-add the nodes to the pools using TMSH commands.

The feature allowing movement of objects appears to be on its way - the release notes for 11.6 show an early access feature giving the ability to move/rename objects:

Object move and rename (early access) This release provides early access to the feature that enables move/rename of specific BIG-IP object types, such as virtual servers, virtual addresses, pools (implicitly moves pool members), nodes, monitors, profiles, iRules, iApps, device names, self IP addresses, iCall, and folders. Note that this functionality is not provided for VLANs or Partitions.

http://support.f5.com/kb/en-us/products/big-ip_ltm/releasenotes/product/relnote-ltm-11-6-0.html