A user renamed the Customer entity record to Client in the Rename Records/Transactions Page.

The user created a custom Center tab named Client under Lists > Relationships. Name changes are applied to standard NetSuite element names, but not to customized elements.

The user renamed the Customer to Client in the English (U.S.) language, but is currently using English UK as the language under Home > Set Preferences > General > Localization > Language.

The user must have at least a Full/Edit level permission to Rename Records/Transactions in order for changes to save.

The user is logged into another role that uses the classic Center tab. Since renaming records or transactions is a user preference, the name change does not apply to that role.