A similar question was poster about a year ago, which resulted in a ticket being created to assist:
https://community.ringcentral.com/ringcentral/topics/changing-the-email-domain-for-stand-alone-glip-and-our-individual-email-addresses

---

I just completed a POC with RC and transitioned from a test company and domain to the actual company and real domain as a new RC customer. Changing company named seemed easy at first DIY, but I had to ensure the change was made everywhere, and that it was also implemented by RC behind the scenes with Billing and Support who still continued to make all references to the test company and not the real company. 

When it came to domain name change I.e. from testco.com to realco.com I had to escalate a case within RC Support over to specific GLIP Support and then from there to GLIP engineering who implemented the change. 

Hope this helps.   

---

Arun, thanks for the extra detail!
I will also try to reach out to the Glip support team.

---