If you need to surrender your GST number for a proprietorship firm while holding a bank CC limit, it's crucial to first obtain a No Objection Certificate (NOC) from your bank. Banks often require an active GST number for CC limits, so confirm this won't affect your facility. After securing bank consent, proceed to cancel your GST registration via the GST portal. Remember to file a final GSTR-10 return within three months of cancellation and update all other relevant registrations.