Ok , so you arrived in Hawaii several days ago and someone arranged for you to get this cheap flower lei. (or maybe you got one at a Luau). That was 5 days ago, it is starting to die, can't take it home, what do you do with it?
Wear it when you visit Pearl Harbor. When you get off the boat at the Memorial, ask the Ranger to cut the string (he/she will have a scissors) . Go over to the open area just above the Arizona , reflect a few moments on what actually happened here and slowly drop your flowers (no string, just flowers) into the water as a symbolic offering.
It is done all the time, it will make you feel good. Perhaps share a flower or two with folks watching. They will appreciate the opportunity to share in the moment. You may even attract a sea turtle or two to the surface .
I always heard that if you throw it into the water, and it comes back closer to you, you will one day return to the islands, and if it goes out away from you. you won't. I have never been there, but I heard the memorial was beautiful. We must never forget what can happen.