Of all my disappointments with Droid, this is the biggest. This is a feature available since the 70's on any garden variety phone and every cell phone I have owned, but the "smart phone" is unable to navigate the simple "switch hook" or "hook flash" operation. I am amazed that even searches for these terms comes up empty when added to "android". And for iPhone enthusiasts, the iPhone can NOT do this either so far as I can determine.
Programmers - here's what people need to be able to do, and why this simple feature is important. It's important because making one 3-way call after another with the first party staying on the line is a much used method of training and selling.
1) Make a call to your associate or trainee
2) Make a call to a 3rd party (switch hook gets dial tone. Dial 2nd number. Switch hook again to join calls)
3) Drop the Second call ONLY (switch hook)
4) Make another 3rd party call (switch hook gets dial tone. Dial 2nd number. Switch hook again to join calls)
5) repeat
Throughout the session the first person you called - the associate or trainee - remains on the line. You should never have to "hang up ALL" and re-initiate the entire call again as the common "add a call" feature forces.
I THINK one model HTC actually has a "flash" button, but I don't have any confirmation the feature works as it should.