Changing existing client's company name without losing data

Updating your client's company name will not result in any data loss, KimRR.

The company file name is simply a label used to identify the file, and it does not affect the underlying data stored within the file. 

To update the client's business name:

1. Log in to your QuickBooks Online Accountant dashboard.
2. From the Clients tab, select the client whose business name you want to update.
3. Click the Edit client.
4. In the Client details section, locate the Business name field.
5. Update the business name with the new name.
6. Click on the Save button to save the changes.

Additionally, it is advisable to regularly create a backup of your data as a precautionary measure to guarantee its safety.

I am happy to help you with any further questions or issues you may have. You can post them anytime in the comment below. Take care!