both at the same time you will not be able to, or you talk to one or the other, for that you have to ask your provider for the waiting call (in some providers it is paid, beware) and with it when you are talking to 1, you will see how calls you 2, you can go to 1 to wait and talk to 2 ..., if you want to do several at the same time you will have to use a conference program ...