Update an existing contract's information. All fields are optional - only include fields you want to change.

Use Cases:

• Update contract value or dates
• Change assigned user
• Set, replace, or clear buyer and seller representatives
• Update property information
• Modify commission details
• Update referral details
• Update custom field values

Updatable Fields:

• Basic info (name, assigned user)
• Buyer and seller representatives (buyerRepresentativeUserId, sellerRepresentativeUserId; null clears user reps on that side)
• Property details
• Contract value and dates (scheduled closing, inspection, actual closing)
• Commission fields (total, buyer, seller with types)
• Referral information
• Custom fields

Write Validation:
Unsupported aliases (amount, close_date, address, property_address, person_id, people, and stage_id, including camelCase variants) return 422 before any changes are saved. Use contractValue, scheduledClosingDate, the split property fields, and primaryPipelineStageId. Contact association writes (contactIds, contactRoleIds, people/person ID aliases) are not supported on update; manage contacts in the contract's settings. Cross-pipeline stages return 422 on every processed attempt, including retries. Custom field keys resolve against the contract type's current fields (the same ones GET returns). An unknown key, a non-scalar value, or a dropdown value outside the field's choices returns 422 naming each rejected key, and nothing in the request is saved. Sending back a dropdown's currently stored value is always accepted.

Note: To change the contract type, create a new contract instead.

Example:

{
  "contractValue": 475000,
  "scheduledClosingDate": "2026-01-15",
  "totalCommission": 14250
}