> ## Documentation Index
> Fetch the complete documentation index at: https://docs.deribit.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Amending an Order
> Amend existing orders using the Starbase Binary API including AmendOrderRequest, AmendOrderResponse, and AmendOrderReject messages.
## Amending an existing order
**Cross-Session Amending**: Orders can be amended from a different SBE session than the one that submitted them. For example, an order submitted on session A can be amended on session B.
**Response Routing**: `AmendOrderResponse` is sent to both the session that sent the `AmendOrderRequest` and the session that originally submitted the order. All subsequent events (fills, further amends, cancels) route to the original submit session.
**Event Scoping**: An SBE connection only receives events about orders submitted through that same connection.
### AmendOrderRequest (110)
Request to change the modifiable fields of an existing order.
**Null values**: Some optional fields use `NULL_LONG` / `NULL_QUANTITY` (`0x8000000000000000L`) as a sentinel to indicate "not set". For example, set `displayAmount = NULL_QUANTITY` to keep the order non-iceberg.
| Field | Name | Type | Length | Description |
| ----- | ------------- | --------- | ------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| 1 | clientOrderId | int64 | 8 | Numeric client order ID |
| 2 | correlationId | int64 | 8 | Client-assigned ID |
| 3 | instrumentId | int64 | 8 | Numeric instrument ID |
| 4 | limitPrice | Price9 | 8 | New price |
| 5 | quantity | Decimal72 | 9 | New quantity |
| 6 | showQty | Decimal72 | 9 | New visible amount for iceberg orders. Setting this field to any value (including equal to `amount`) marks the order as an iceberg order. To submit a non-iceberg order, omit this field or set it to `NULL_QUANTITY`. Iceberg orders are not supported for options and combo instruments. |
| 7 | flags | uint16 | 2 | See the table below. |
The table below outlines the content of field 7 (flags) of `AmendOrderRequest`.
| Bit number (from last to first) | Name | Description |
| ------------------------------- | ----------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 1 | postOnly | Enables post-only that amends the order to the best bid/ask if the edit would make it immediately executable. The amended price is then validated against price limits. Mutually exclusive with `postOnlyReject`. |
| 2 | postOnlyReject | Enables post-only that rejects the edit if it would make the order immediately executable. The original order remains in the book unchanged. Mutually exclusive with `postOnly` . |
| 3 | Reserved for future use | |
| 4 | Reserved for future use | |
| 5 | Reserved for future use | |
| 6 | Reserved for future use | |
| 7 | Reserved for future use | |
| 8 | Reserved for future use | |
| 9-16 | Reserved for future use | |
### AmendOrderResponse (210)
Response to confirm an `AmendOrderRequest` was successful, sent from the exchange to the client. Any immediate fills generated by the `AmendOrderRequest` will be included in the `AmendOrderResponse` and will NOT be sent additionally in an `OrderUpdate`.
If the amendment causes the order to aggress and it is speed bumped, the `AmendOrderResponse` is sent immediately with `orderState = 4` (queued). Once the speed bump period expires, an unsolicited `OrderPlaced` message is sent. See [Speed Bumps](/starbase/speed-bumps) for details.
| Field | Name | Type | Length | Description | | | |
| ----- | ------------------ | --------- | ------ | --------------------------------------------------------------------------------------------------------------------------------------------------------- | - | ----------------------------------------- | ----------------------------------------- |
| 1 | transactTime | int64 | 8 | Nanoseconds since epoch. Time of entry into the order book | | | |
| 2 | execId | int64 | 8 | Exchange-assigned event ID | | | |
| 3 | clientOrderId | int64 | 8 | Numeric client order ID | | | |
| 4 | correlationId | int64 | 8 | Client-assigned ID | | | |
| 5 | orderId | int64 | 8 | Numeric exchange assigned order ID | | | |
| 6 | instrumentId | int64 | 8 | Numeric instrument ID | | | |
| 7 | limitPrice | Price9 | 8 | Price. Can differ from submitted price when post-only (amend) is enabled | | | |
| 8 | quantity | Decimal72 | 9 | Quantity. Can differ from submitted quantity when reduce-only is enabled | | | |
| 9 | totalFilled | Decimal72 | 9 | Filled quantity | | | |
| 10 | visibleQty | Decimal72 | 9 | Currently visible in market data | | | |
| 9 | totalFilled | Decimal72 | 9 | Filled quantity | | | |
| 10 | visibleQty | Decimal72 | 9 | Currently visible in market data | | | |
| 11 | receiveTime | int64 | 8 | Nanoseconds since epoch. Time of receipt of order on the gateway. | | | |
| 12 | status | int8 | 1 | `1`=Active
`2`=filled
`3`=cancelled
`4`=queued (speed bumped) | | | |
| 13 | cancelReason | int8 | 1 | See [Cancel Reason Codes](/starbase/binary-api-reference#cancel-reason-codes) | | | |
| 14 | blockLengthOfFills | uint16 | 2 | 24 (bytes) | | | |
| 15 | numberOfFills | uint16 | 2 | Indicates the length of the following repeating group containing all immediate fills when the order was submitted | | | |
| ->16 | matchId | int64 | 8 | Transaction ID representing match, shared by all fills within match | | | |
| ->17 | fillPrice | Price9 | 8 | Price of fill | | | |
| ->18 | fillQty | Decimal72 | 9 | Quantity of fill | | | |
| 19 | blockLengthOfLegs | uint16 | 2 | 33 (bytes) | | | |
| 20 | numberOfLegs | uint16 | 2 | Indicates the length of the following repeating group containing all combo leg quantities and prices.
Non-zero for trades on combo instruments only. | | | |
| ->21 | matchId | int64 | 8 | Transaction ID representing match. | | | |
| ->22 | instrumentId | int64 | 8 | Numeric instrument ID. | | | |
| ->23 | legPrice | Price9 | 8 | Price9 | 8 | Price of this leg in the combo instrument | Price of this leg in the combo instrument |
| ->24 | legQty | Decimal72 | 9 | Quantity of this leg in the combo instrument | | | |
| ->25 | legSide | int8 | 1 | `1`=BUY
`-1`=SELL | | | |
### AmendOrderReject (212)
Reject generated in case an `AmendOrderRequest` is unsuccessful.
| Field | Name | Type | Length | Description |
| ----- | ------------- | ----- | ------ | ------------------------------------------------------------------------------------------------------------------------------- |
| 1 | transactTime | int64 | 8 | Nanoseconds since epoch. Time of entry into the order book |
| 2 | execId | int64 | 8 | Exchange-assigned event ID |
| 3 | clientOrderId | int64 | 8 | Numeric client order ID |
| 4 | correlationId | int64 | 8 | Client-assigned ID |
| 5 | orderId | int64 | 8 | Numeric exchange assigned order ID |
| 6 | instrumentId | int64 | 8 | Numeric instrument ID |
| 7 | reason | int8 | 1 | Rejection reason code. See [Rejection Reason Codes](/starbase/binary-api-reference#rejection-reason-codes) for possible values. |
| 8 | details | char | 0-255 | ASCII-encoded string |