@prodromos

If you just want to replace all instruments in the existing instrumentList, you can use the ReplaceAllWithIdentifiers endpoint. Below is the sample of request.

POST https://hosted.datascopeapi.reuters.com/RestApi/v1/Extractions/InstrumentLists('0x06999f9753507bcf')/ThomsonReuters.Dss.Api.Extractions.InstrumentListReplaceAllWithIdentifiers

Body:

{
  "Identifiers": [
    {
      "Identifier": "IBM.N",
      "IdentifierType": "Ric"
    },
    {
      "Identifier": "JPY=",
      "IdentifierType": "Ric"
    },
    {
      "Identifier": "EUR=",
      "IdentifierType": "Ric"
    }
  ],
  "KeepDuplicates": false
}

@prodromos,

There is an API call to retrieve the list of items (i.e. instruments) in an existing list:

GET https://hosted.datascopeapi.reuters.com/RestApi/v1/Extractions/InstrumentLists('0x06999f9753507bcf')

where 0x06999f9753507bcf is the instrument list ID.

This delivers all instruments, each with their identifier and individual ID in the list. That ID can be used to remove a specific instrument from a list, using:

DELETE https://hosted.datascopeapi.reuters.com/RestApi/v1/Extractions/InstrumentListItems('VjF8MHgwNjk5OWY5NzUzNTA3YmNmfDE')

where VjF8MHgwNjk5OWY5NzUzNTA3YmNmfDE is the ID of the instrument in the instrument list.

Using these 2 calls you can easily remove instruments from an existing list.

Using the append identifier call you can also add instruments:

POST https://hosted.datascopeapi.reuters.com/RestApi/v1/Extractions/InstrumentLists('0x06999f9753507bcf')/ThomsonReuters.Dss.Api.Extractions.InstrumentListAppendIdentifiers

Body:

{
    "Identifiers": [
        {
            "Identifier": "IBM.N",
            "IdentifierType": "Ric",
            "UserDefinedIdentifier": "UserIdent4A"
        }
    ],
    "KeepDuplicates": false
}

These calls therefore allow you to manage your instrument list without deleting it.

These calls are described here in the API Reference Tree. You will also be able to run them using the C# example application, described in the Quick Start (see under section "Instrument List Examples").