/loan/{loan_id}

Updates a loan.
- When the loan is SUBMITTED or TO_VALIDATE, all the below fields can be updated.
- When the loan is VALIDATED or SCHEDULED, the references and to_repay_at fields can be updated.
- When the loan is TO_REPAY, only the to_repay_at change be changed. The earliest acceptable date being loan.earliest_to_repay_at.

        This operation is not available when the loan is in another status.