diff --git a/models/formatter.go b/models/formatter.go
index b7035d9..de6d30e 100644
--- a/models/formatter.go
+++ b/models/formatter.go
@@ -67,8 +67,8 @@ type CallStat struct {
 	ClientId                  int    `gorm:"index"`
 	CustomerDnis              string
 	CustomerAni               string
-	ConversationStart         time.Time `gorm:"index"`
-	ConversationEnd           time.Time `gorm:"index"`
+	ConversationStart         *time.Time `gorm:"index"`
+	ConversationEnd           *time.Time `gorm:"index"`
 	SearchStartTime           *time.Time
 	P1ConnectTime             time.Time `gorm:"index"`
 	P1DisconnectTime          time.Time `gorm:"index"`