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FeaturesagentOS Direct DebitUpdated March 20, 2026

Amending a Collection Amount

Amending a Collection Amount

Version 1.0.88 introduces the ability for agents to change the collection amount on an active Direct Debit mandate. Because BACS operates on advance-notice rules, the amendment is future-dated and a notification is automatically sent to the tenant.

How It Works

1. Submit the Amendment

An agent submits a new collection amount against an active mandate via the UI or API. The system validates the request and calculates the earliest permissible effective date based on BACS advance-notice requirements.

2. Future-Dated Amendment Record

Instead of updating the collection amount immediately, the system creates a pending amendment record attached to the mandate. The current collection amount remains in effect until the effective-from date is reached.

3. Effective-From Date

The calculated effective-from date is returned to the agent immediately on submission. This date represents when the new amount will first be applied to a collection run. The date accounts for:

  • BACS advance-notice period (minimum notice required under the Direct Debit Guarantee)
  • UK banking working days

4. Tenant Notification

A notification is automatically dispatched to the tenant informing them of the upcoming change, the new amount, and the date from which it applies. This satisfies the advance-notice requirement under the Direct Debit Guarantee.

5. Modulr AUDDIS Submission

An Inngest background job monitors pending amendments and submits the AUDDIS amendment message to Modulr at the appropriate point in the BACS processing window — no manual intervention is required.

API Usage

See the API Reference — Mandate Amount Amendment page for endpoint details, request/response shapes, and error codes.

Mandate States

While an amendment is pending, the mandate remains active and collections continue at the existing amount. The pending amendment and its effective-from date are visible on the mandate detail. Once the Inngest job submits the AUDDIS message and the effective date is reached, the mandate amount is updated automatically.

Direct Debit Guarantee Compliance

All amount amendments must satisfy the advance-notice obligations of the UK Direct Debit Guarantee. The system enforces this automatically — agents cannot set an effective date that falls within the required notice window. Tenants receive written notification in all cases.