You can update a clients session created earlier with the PATCH /client-session API call.
The only required field for the request is clientToken. Other supported request fields are same as for the POST /client-session API call.
You need to specify only the fields you wish to update. However, if the items that are to be updated are of type array, then you need to provide the complete array along with modified items.
If you wish to update nested fields on the client session, such as the customer emailAddress field, you can pass the customer object with only one field, emailAddress, to update.
If you simply wish to clear the value of the field, pass null as your input.
You can update paymentMethod.vaultOnSuccess field but updating of the paymentMethod.options field through PATCH /client-session is not supported.
The response will contain all the fields of the client session including the ones that were changed.