One table is out of use for a week. Can I stop just that one?

Yes. Find it under Settings → Tables & QR ordering, untick Accepting scans and Save. Scanning that card then shows your normal ordering page instead of a table order, the table drops out of the QR print pack, and it stops showing on the floor of your devices. Tick it back when the table returns. The same printed card works again and there is nothing to reprint.