[asterisk-users] transferring a not yet answered call

[gincantalupo]

Hi,
how can I transfer a not yet answered call?
Suppose you have a secretary and you want her to call someone for you 
(seems to be very common if you have a secretary  :-) ).
She calls person A then in some way she has to connect the called person 
A with another person B (the person who order to call, for example you).
How can it be done?

Thank you!

Giorgio.