Amendment or cancellation of a Simplified Frontier Declaration (SFD)

Hello We are a business authorised for Simplified Customs Declaration Process (SCDP). Our customs brokers do import frontier declaration (SFD). We then send the supplementary declaration (SDI) using a software later in the month. When we find errors in import SFDs, we ask agents to correct them. It is a pain to get a response from them let alone confirmation of amendment. Can we, traders, just go direct to HMRC and request an SFD amendment and skip the customs broker? Thank you!

have you seen this latest update ? https://www.gov.uk/government/publications/import-and-export-change-or-cancel-a-customs-freight-simplified-procedures-simplified-frontier-declaration-sfd

Good Afternoon,
Please could you direct this query to your SCDP supervising office.
Their details should be included within your SCDP approval letter.  
Thankyou.
Regards.