var conversation;

        // ...
        // Here we choose conversation that we want to transfer to another number.
        // ...

        // Number to which conversation will be transferred.
        var number = "1111";

        if(conversation1.capabilities.canTransfer)
        {
            // Initiating transfer of conversation to number "1111";
            conversation.transfer(number);

            // Completing initiated conversation transfer.
            conversation.completeTransfer();
        }