iOS 11 Update

Hello,

I'm not able to update my iPhone 6 Plus. The software is downloaded and there's no "red flags" as to why it can't download. It just pops up with a notification that says "Unable To Install Update -- An error occurred installing iOS 11". It's not the wifi connection - I've already checked to see if that was the cause. this is really urgent as I'm leaving on a 5:30 flight tomorrow morning and am only having these problems now. What should I do next?

Thank you,

Anna G*

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