Can I Change the Date of a Client Advance without Adjusting the Voucher?

Call up the Client-Matter in Bill Preparation and set your cut-off date so the Client Advance will be included on the Expenses/Client Advance Tab and then locate the transaction on the Expenses/Client Advance Tab.  Highlight it and then click ACTION, Global Edit.  Enter the new date in the date field and click OK.  Save your changes in Bill Preparation.  Change the cut-off date in Bill Preparation to the cut-off date you actually want to use and generate your Invoice.