Bootstrapping existing nodes in bulk

We have an established pool of 165 nodes that have until now been part of two separate Chef organizations. We are combining the two organizations into one, and are migrating the nodes into the new merged organization. The migration part is done, but the /etc/chef/client.rb file on each of the nodes still points to the old organization. I want to update the client.rb file on all the nodes to point to the new organization, but I still want all the nodes to retain their existing runlists. Is there an easy way to do this?

I last used this tool: https://github.com/mdxp/knife-backup

I’ve not tested it with the most recent versions of chef, and it took some review of the output of it to restore only the desired node configurations onto the new server. It also preserved any manually set node attributes that had been set to override default attributes for that node specifically, and was useful for backing up roles, cookbooks, environments, and databags as well to ensure consistency between chef servers. I just had to be really careful with it to restore only the content I wanted restored.