a0d929ca_WSRP_v2_0_Specification__Statement_text
[#] CS078 [Section] 5.4.3 [Statement text] 
If the Producer returns a new portletHandle without returning a new sessionID, the Consumer MUST associate the current sessionID with the new portletHandle rather than the previous portletHandle.
WSRP v2.0 Specification
Statement text