---
title: "Create duration modification details"
method: POST
path: "/leases/{lease_id}/amendments/{amendment_id}/duration-detail"
tags: ["Amendment Duration Details"]
---

# Create duration modification details

`POST /leases/{lease_id}/amendments/{amendment_id}/duration-detail`

## Request

- Base URL: `https://api.faireplace.com/api`
- URL: `https://api.faireplace.com/api/leases/{lease_id}/amendments/{amendment_id}/duration-detail`
- Auth: HTTP bearer

Create the duration detail for a `DURATION_MODIFICATION` or `RENEWAL` amendment. Only one duration detail can exist per amendment (1:1 relationship).

**Validation rules:**
- For extensions/renewals: `new_end_date` must be > `previous_end_date`
- For reductions/early termination: `new_end_date` can be <= `previous_end_date`

## Path parameters

- `lease_id` string, uuid, required
- `amendment_id` string, uuid, required

## Request body

- CreateAmendmentDurationDetailDto: Data for creating duration modification details
  - `previous_end_date` string, date, required
  - `new_end_date` string, date, required
  - `extension_type` 'RENEWAL' | 'EXTENSION' | 'REDUCTION' | 'EARLY_TERMINATION', required
  - `reason_code` string, nullable
  - `reason_details` string, nullable

## Response `201`

Duration detail created

- AmendmentDurationDetailResponse: Duration modification details for a DURATION_MODIFICATION or RENEWAL amendment (1:1 relationship)
  - `id` string, uuid, required
  - `amendment_id` string, uuid, required
  - `previous_end_date` string, date, required: Previous lease end date
  - `new_end_date` string, date, required: New lease end date. Must be > previous_end_date for extensions (not for REDUCTION/EARLY_TERMINATION)
  - `extension_type` 'RENEWAL' | 'EXTENSION' | 'REDUCTION' | 'EARLY_TERMINATION', required: Type of duration change
  - `reason_code` string, nullable: Reason code
  - `reason_details` string, nullable: Detailed reason

## Other responses

- `400`: Bad request
- `401`: Unauthorized
- `409`: A duration detail already exists for this amendment
- `422`: Unprocessable Entity

---

[API](https://skmtc.dev/faireplace/apis/faireplace-property-management-api.md) · [All operations](https://skmtc.dev/faireplace/apis/faireplace-property-management-api/llms.txt) · [OpenAPI document](https://skmtc.dev/faireplace/apis/faireplace-property-management-api/revisions/69de39762919?raw)