Provide a dial plan entry in the second FS that handles the call appropriately after the deflect or transfer.
uuid_deflect or uuid_transfer, depending on whether the call has been answered by the first FS instance or not. See the wiki.
* *>>* 2.Receive a call from another FS
* This question can be separated into two part: *>>* 1.Pass a call to another FS
You haven't explained what you're trying to do - a general question warrants a general answer. I am assuming the call is arriving at one FS system, and (before or after answering it), you want to move it to another FS system. That's the question I've answered above. The wiki documents the syntax.
SorrySorry,let me explain my question. When User1( User of FS1 ) call User2( User of FS2 ) , FS1 will pass the call to FS2 before answering, and then User1 can talk with User2. -Brad