Is "unexpected occurence" the phrase that I need here in this context?

Question

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While awaiting confirmation from Hotel A about the possibility of the six days’ reservation for His Excellency, if it is okay with you, we would like to look for a hotel near the area of the Conference, as a backup or alternative plan, in order to ensure accommodations during His Excellency's attendance at the Conference.

Therefore, we would like to request your approval beforehand to allow us to book a hotel room for His Excellency in case of *unexpected occurrence*.

Answer 1

It would be better as "any unexpected occurence".

Answer 2

Or maybe, 'in case of any unforeseen circumstance'.