If the location field on your invoice or work order appears grayed out and won't let you make changes, this is expected behavior — not a bug. The location field is tied to the invoice prefix, which is set to a specific location at the moment a quote is converted to an invoice. Once that conversion happens, the location is locked to preserve the integrity of the invoice numbering and prefix settings.
If the quote has not yet been converted to an invoice, the location can be changed freely at the quote level. The lock only applies after conversion.
Workaround: Duplicate the Quote and Re-Convert
Since the location cannot be changed directly on a converted invoice or work order, the only way to correct it is to go back to the quote stage, duplicate it with the correct location, and convert the duplicate to a new invoice.
Navigate to the original quote associated with the invoice.
Duplicate the quote using Quote Actions → Duplicate Quote. See How to Duplicate a Quote for step-by-step instructions.
On the duplicate quote, update the Location field to the correct location.
Convert the duplicate quote to a new invoice. See How to Send a Quote & Convert to an Invoice.
If purchase orders were already placed on the original work order, they will not carry over to the new work order. You will need to recreate those POs on the new work order after conversion.