diff --git a/source3/libnet/libnet_join.c b/source3/libnet/libnet_join.c
index 2994c3f59dd..fe7fb7dd733 100644
--- a/source3/libnet/libnet_join.c
+++ b/source3/libnet/libnet_join.c
@@ -398,7 +398,7 @@ static WERROR do_unjoin_modify_vals_config(TALLOC_CTX *mem_ctx,
 		W_ERROR_NOT_OK_RETURN(werr);
 	}
 
-	reg_deletevalue(key, "realm");
+	werr = libnet_smbconf_delparm(mem_ctx, "GLOBAL", "realm");
 
 	return werr;
 }