Can I upgrade the response level mid-contract?

Yes. Upgrading from 8-hour to 2-hour response, or from remote support to plans including on-site visits, only requires paying the difference — no re-signing. Temporary upgrades are supported too, such as a priority-response channel during business peaks, billed by day. Downgrades are equally supported with pro-rated refunds. ZhongLianDa builds maintenance plans around customer needs.