Without more info, hard to say what you should do. But without resorting to market timing per se, sometimes market highs can be a good time to reassess your risk tolerance.
If you feel nervous all the time or are nearing retirement, and feel like you need a lower risk portfolio, then make a permanent change to your asset allocation. But don't trade in and out, especially if you have a long time horizon. Te L2040 is basically 25% bonds. So if you want a somewhat lower risk fund, move to the L2030 which is 35% bonds. Or, as some mention, make your own portfolio so you can rebalance yourself. But if you are young or don't have a big balance yet, your positions are likely reasonable.