If you are referring to Ko Olina, they will not allow any umbrellas at the beach of the lagoons.
If you want any shade, you have to rent a beach cabana.
I have seen security make people take umbrellas down on several occasions.
This whole thing with umbrellas is just amazing to me. And yet maybe you can rent them, but you can't use your own? I'm not going to choose a resort to go to based upon an umbrella policy........ It seems silly.
Maybe I need to find a list of beaches in HA that allow umbrellas vs a list of those that do not.