Disable hold music?

Is there a way to disable hold music on my Comcast phone line? That is, when I get the beep that indicates I have another incoming call, I press my receiver down once to put the current call on hold and go to the incoming call. But when I do this, the first call automatically plays hold music, even if I have muted the line on my handset. Very annoying to other parties during conference calls.

If there is no way to disable the hold music, can I disconnect the first call and take the second call, much as I can do on my iPhone? What key or receiver press would do this, rather than putting the first call on hold?

Thanks,

Scott