The option to merge QuickBooks Online (QBO) companies is unavailable, troutmanenterprises.
What you can do is import your Chart of Accounts from one company to another.
You can transfer lists to your QBO company as well. These are customers, vendors, and product lists. Take a look at this article for more details: Move your lists to QuickBooks Online.
You can select which company to keep and make sure to cancel to avoid double charges.
Let me know if you have additional questions.