diff --git a/csi.proto b/csi.proto
index f38392ea..2d81068e 100644
--- a/csi.proto
+++ b/csi.proto
@@ -1200,10 +1200,12 @@ message Snapshot {
   // The ID of the volume group snapshot that this snapshot is part of.
   // It uniquely identifies the group snapshot on the storage system.
   // This field is OPTIONAL.
-  // If this snapshot is a member of the volume group snapshot, the SP
-  // SHOULD provide the ID of the volume group snapshot in this field.
-  // If provided, CO MUST use this field to indicate that this snapshot
-  // is part of the specified group snapshot.
+  // If this snapshot is a member of a volume group snapshot, and it
+  // CAN NOT be deleted as a stand alone snapshot, then the SP
+  // MUST provide the ID of the volume group snapshot in this field.
+  // If provided, CO MUST use this field in subsequent snapshot volume
+  // group operations to indicate that this snapshot is part of the
+  // specified group snapshot.
   // If not provided, CO SHALL not indicate this snapshot is part of
   // a group snapshot and allow it to be deleted separately.
   // If this message is inside a VolumeGroupSnapshot message, the value
diff --git a/lib/go/csi/csi.pb.go b/lib/go/csi/csi.pb.go
index e0ae1cec..084d4d66 100644
--- a/lib/go/csi/csi.pb.go
+++ b/lib/go/csi/csi.pb.go
@@ -3310,10 +3310,12 @@ type Snapshot struct {
 	// The ID of the volume group snapshot that this snapshot is part of.
 	// It uniquely identifies the group snapshot on the storage system.
 	// This field is OPTIONAL.
-	// If this snapshot is a member of the volume group snapshot, the SP
-	// SHOULD provide the ID of the volume group snapshot in this field.
-	// If provided, CO MUST use this field to indicate that this snapshot
-	// is part of the specified group snapshot.
+	// If this snapshot is a member of a volume group snapshot, and it
+	// CAN NOT be deleted as a stand alone snapshot, then the SP
+	// MUST provide the ID of the volume group snapshot in this field.
+	// If provided, CO MUST use this field in subsequent snapshot volume
+	// group operations to indicate that this snapshot is part of the
+	// specified group snapshot.
 	// If not provided, CO SHALL not indicate this snapshot is part of
 	// a group snapshot and allow it to be deleted separately.
 	// If this message is inside a VolumeGroupSnapshot message, the value
diff --git a/spec.md b/spec.md
index 7733a8b2..94fd6143 100644
--- a/spec.md
+++ b/spec.md
@@ -1910,10 +1910,12 @@ message Snapshot {
   // The ID of the volume group snapshot that this snapshot is part of.
   // It uniquely identifies the group snapshot on the storage system.
   // This field is OPTIONAL.
-  // If this snapshot is a member of the volume group snapshot, the SP
-  // SHOULD provide the ID of the volume group snapshot in this field.
-  // If provided, CO MUST use this field to indicate that this snapshot
-  // is part of the specified group snapshot.
+  // If this snapshot is a member of a volume group snapshot, and it
+  // CAN NOT be deleted as a stand alone snapshot, then the SP
+  // MUST provide the ID of the volume group snapshot in this field.
+  // If provided, CO MUST use this field in subsequent snapshot volume
+  // group operations to indicate that this snapshot is part of the
+  // specified group snapshot.
   // If not provided, CO SHALL not indicate this snapshot is part of
   // a group snapshot and allow it to be deleted separately.
   // If this message is inside a VolumeGroupSnapshot message, the value