Available in Sage 50 Premium Accounting and higher.
If a time ticket displays the flag Has this ticket been applied to an invoice, this indicates that the ticket has already been applied to a customer invoice. You can only apply a time or expense ticket once to customer invoices. After the ticket has been applied to a sales invoice, you cannot apply the ticket again.
Note: If you delete a line item that references an applied ticket in the sales invoice, the ticket will still indicate that it has been used in Sales/Invoicing. You will not be able to apply it to another invoice. To keep your ticket transactions consistent with your sales invoices, you should delete the entire invoice and re-create it, omitting the line that you want to delete. Tickets marked Has this ticket been applied to an invoice cannot be deleted. In order to remove the used ticket, you must purge the ticket.