a0d929ca_WSRP_v2_0_Specification__Statement_text
[#] CS083 [Section] 5.6 [Statement text] 
The Consumer MAY inform the Producer that it will no longer be using a set of sessions by invoking releaseSessions (e.g. the Consumer is releasing resources related to the sessionIDs):
WSRP v2.0 Specification
Statement text