update remote participant management section

Author: chengyuanlai-msft

articles/communication-services/quickstarts/voice-video-calling/includes/video-calling/video-calling-android.md

@@ -610,6 +610,8 @@ private void answerIncomingCall() {
 
 ## Remote participant and remote video streams
 
+All remote participants are available through the `getRemoteParticipants()` method on a call instance. Once the call is connected, we can access the remote participants of the call and handle the remote video streams.
+
 When you start a call or answer an incoming call, you need to subscribe to the `addOnRemoteParticipantsUpdatedListener` event to handle remote participants. 
 
 ```java
@@ -621,6 +623,8 @@ When you use event listeners that are defined within the same class, bind the li
 
 If you try to pass the listener in directly as an argument, you lose the reference to that listener. Java creates new instances of these listeners, not referencing previously created ones. You can't remove prior instances, because you don’t have a reference to them.
 
+> Note: When a user joins a call, they can access the current remote participants through the `getRemoteParticipants()` method. The `addOnRemoteParticipantsUpdatedListener` event will not trigger for these existing participants. This event will only trigger when a remote participant joins or leaves the call while the user is already in the call. 
+
 ### Remote video stream updates
 
 For 1:1 calling, you need to handle added participants. When you remove the remote participant, the call ends. For added participants, you subscribe to `addOnVideoStreamsUpdatedListener` to handle video stream updates.

articles/communication-services/quickstarts/voice-video-calling/includes/video-calling/video-calling-ios.md

@@ -632,6 +632,8 @@ public class CallObserver: NSObject, CallDelegate, IncomingCallDelegate {
 
 All remote participants are represented with the `RemoteParticipant` type and are available through the `remoteParticipants` collection on a call instance.
 
+> Note: When a user joins a call, they can access the current remote participants through the `RemoteParticipants` collection. The `didUpdateRemoteParticipant` event will not trigger for these existing participants. This event will only trigger when a remote participant joins or leaves the call while the user is already in the call. 
+
 We can implement a `RemoteParticipantObserver` class to subscribe to the updates on remote video streams of remote participants.
 
 ```Swift

articles/communication-services/quickstarts/voice-video-calling/includes/video-calling/video-calling-windows.md

@@ -899,6 +899,7 @@ call = await incomingCall.AcceptAsync(acceptCallOptions);
 ### Remote participant and remote video streams
 
 All remote participants are available through the `RemoteParticipants` collection on a call instance. Once the call is connected, we can access the remote participants of the call and handle the remote video streams. 
+> Note: When a user joins a call, they can access the current remote participants through the `RemoteParticipants` collection. The `OnRemoteParticipantsUpdated` event will not trigger for these existing participants. This event will only trigger when a remote participant joins or leaves the call while the user is already in the call. 
 
 ```C#
 private async void Call_OnVideoStreamsUpdatedAsync(object sender, RemoteVideoStreamsEventArgs args)