diff --git a/33128/r18/TS33128Payloads.asn b/33128/r18/TS33128Payloads.asn
index 684199402eeff3b9fae5ad1a0694eb0e94bdb91d..1e1771d9cbd0573d40de1c8d2f9a1098d99ce5ba 100644
--- a/33128/r18/TS33128Payloads.asn
+++ b/33128/r18/TS33128Payloads.asn
@@ -4342,7 +4342,7 @@ RCSSessionEstablishment ::= SEQUENCE
     rCSSessionType          [6] RCSSessionType,
     sessionDirection        [7] Direction,
     rCSSessionMessage       [8] RCSSIPSessionMessage,
-    location                [9] Location
+    location                [9] Location OPTIONAL
 }
 
 -- See clause 7.13.3.4.3.1 for details of this structure
@@ -4357,7 +4357,7 @@ RCSSessionModification ::= SEQUENCE
     sessionDirection        [7] Direction,
     sessionEndpoints        [8] RCSSessionEndpoints,
     rCSSIPSessionMessage    [9] RCSSIPSessionMessage,
-    location                [10] Location
+    location                [10] Location OPTIONAL
 }
 
 -- See clause 7.13.3.4.4.1 for details of this structure
@@ -4369,7 +4369,7 @@ RCSSessionRelease ::= SEQUENCE
     rCSSessionType          [4] RCSSessionType,
     sessionDirection        [5] Direction,
     rCSSIPSessionMessage    [6] RCSSIPSessionMessage,
-    location                [7] Location
+    location                [7] Location OPTIONAL
 }
 
 -- See clause 7.13.3.5 for details of this structure