diff --git a/db/kvstore/client.go b/db/kvstore/client.go
index a7cbf2b..a8e6311 100644
--- a/db/kvstore/client.go
+++ b/db/kvstore/client.go
@@ -75,10 +75,10 @@
 
 // Client represents the set of APIs  a KV Client must implement
 type Client interface {
-	List(key string, timeout int) (map[string]*KVPair, error)
-	Get(key string, timeout int) (*KVPair, error)
-	Put(key string, value interface{}, timeout int) error
-	Delete(key string, timeout int) error
+	List(key string, timeout int, lock ...bool) (map[string]*KVPair, error)
+	Get(key string, timeout int, lock ...bool) (*KVPair, error)
+	Put(key string, value interface{}, timeout int, lock ...bool) error
+	Delete(key string, timeout int, lock ...bool) error
 	Reserve(key string, value interface{}, ttl int64) (interface{}, error)
 	ReleaseReservation(key string) error
 	ReleaseAllReservations() error