How do I cancel a BOC-3 filing?
You do not directly "cancel" a BOC-3 — you replace it with a new one filed by a different process agent, or your operating authority is revoked and the BOC-3 becomes moot. The FMCSA only accepts a fresh BOC-3 to supersede an existing designation; an attempted "withdrawal" by the carrier alone leaves the prior designation on file until something replaces it.
The federal regulation at 49 CFR §366.4 requires every motor carrier, broker, and freight forwarder with active interstate operating authority to maintain a BOC-3 on file at all times. There is no procedural path for a carrier to take itself out of compliance with §366 while keeping its operating authority active. The only way the BOC-3 designation is withdrawn from FMCSA records is by replacement (a new BOC-3 from a different process-agent provider supersedes the old one) or by operating-authority revocation (when the MC is revoked, the BOC-3 becomes irrelevant).
For carriers switching process-agent providers, the new provider files a fresh BOC-3 on Form BOC-3 and the FMCSA L&I system replaces the prior designation in SAFER on the next refresh cycle. The outgoing provider is automatically dropped from the FMCSA record; the carrier does not need to separately notify the prior provider for the SAFER record to update, though most providers ask for a formal cancellation notice for their own subscription billing.
For carriers shutting down operations, the path is to file Form MCS-150 with intent to deactivate the USDOT (or to allow the operating authority to be involuntarily revoked for non-renewal of the §387 financial-responsibility filing). Once the authority is revoked, the BOC-3 designation is effectively dead, and any subscription auto-renewal can be stopped with the provider directly.
Carriers who only want to stop paying an annual-renewal subscription should switch to a flat-fee provider rather than try to cancel. A flat-fee BOC-3 (one-time $50-$75) replaces the annual-renewal designation in SAFER, and the prior provider's subscription auto-cancels when the carrier doesn't pay the next year. The §366.4 obligation continues to be met because the new flat-fee designation is on file.