Change the state of a signature request.

Use this operation to transition a stateful signature request to a new state.

Possible transitions are:

• from DRAFT to PENDING: start the signature request: the platform waits for the activation date (only if set) and transitions the signature request to IN_PROGRESS automatically
• from PENDING to DRAFT: suspend the signature request so that it can be updated
• from PENDING to CANCELED: cancel the signature request without waiting for the activation date
• from IN_PROGRESS to CLOSED: close the signature request before all signatures get collected
• from IN_PROGRESS to CANCELED: cancel the signature request before all signatures get collected

Note that stateless signature requests can only be transitioned to CLOSED or CANCELED,
which triggers the generation of the audit trail and its signature by the platform.