Timesheet Button Label Change for Users without Managers

Currently for users without a manager, the close button label is "Save and Close Timesheet".

Whereas, for users with a manager, the close button label is "Submit for Approval".

We would like an option to change the button labels to "Submit", either as an enterprise system administration control or hard-coded change to the Workfront production environment, to improve the user experience (i.e. minimise confusion).