Should we consider the case that Sender can change SSRC during one RTP session?

If there is just one video or audio media section (m=/mid), there is no RID and no SSRC provided in remote description. This implicates that receiver should link received SSRC to this only one media section (mid) when received the first RTP packet.

However, Sender may change SSRC during one RTP session. How to handle it? 

Create multiple tracks in RtpReceiver?