More than likely, this is already a BOOKING. The eCM will only report an invoice to XERO for private hire jobs if this job has already been converted into a booking.
When updating a Private Hire Booking, follow the steps below:
Convert the Job back to a Pending Quote
Make amendments to the Price of the Job
Quick Save the Job
Convert the Job back to a Booking
Check Xero to confirm
"What if I already deleted or voided the invoice in XERO?"
Unfortunately, the eCM does not have the right to access XERO's database and system. A workaround for this is to Duplicate the Job in the eCM, convert it to a booking, and let eCM report the invoice to XERO as the system is designed to. Once you have confirmed the invoice in XERO, you can then go back to the eCM to delete the original Job and make sure your customer gets the new Job ID of the duplicated Job for reference when making payments.