Transferring active call to another destination

gistfile1.cs

public class TransferCommand : ICommand
{
    private ISipUserAgent _userAgent;
    private TransferArguments _arguments;

    public TransferCommand(ISipUserAgent userAgent, TransferArguments transferArguments)
    {
        _userAgent = userAgent;
        _arguments = transferArguments;
    }

    public void Execute()
    {
        _userAgent.CallManager.GetCallById(int.Parse(_arguments.CallId)).Transfer(_arguments.Destination);
    }
}