eth_cancelBundle

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "eth_cancelBundle",
  "params": [
    {
      replacementUuid,   // String, UUID that was provided during eth_sendBundle.
    }
  ]
}

For more info on bundle replacement visit https://www.shimmerblocks.com/api/eth_sendbundle#bundle-replacement