diff --git a/lib/liblynq-sim/include/lynq_sim.h b/lib/liblynq-sim/include/lynq_sim.h
index 9e55e69..e7f534f 100755
--- a/lib/liblynq-sim/include/lynq_sim.h
+++ b/lib/liblynq-sim/include/lynq_sim.h
@@ -27,6 +27,7 @@
 int lynq_change_pin(char *old_pin, char *new_pin);
 int lynq_unlock_pin(char *puk, char *pin);
 int lynq_query_phone_number(char buf[]);
+int lynq_switch_card(int slot);
 /*add by lei*/