Update specific properties of a contract. The following fields can be modified:

• next_charge: Next charge date or 'now'
• occurrences: Total number of charges
• next_payment: Next payment attempt date
• payment_method: New payment method ID
• amount: New charge amount (creates new contract)
• resume: Resume cancelled contract
• scheduled_date: New schedule date
• status: SUSPENDED/ACTIVE
• metadata: Custom key-value pairs stored on the contract
• alt_key: Your reference for the contract
• description: Payment description
• event_date: Event date
• charges: Add, update, or remove scheduled charges on a scheduled-charges contract
• modify_in_place: Edit the existing contract and its charges directly instead of cancelling and cloning (only relevant when charges is supplied)

Resume restriction: when resuming a cancelled or suspended contract (by setting resume: true or status: ACTIVE), you cannot change amount, frequency, charges, event_date, payment_method, or legal_entities in the same request.