Twice daily event for island set up, open to change (8)
I believe the answer is:
editable
'twice daily event for island set up' is the definition.
I can't judge whether this defines the answer.
'open to change' is the wordplay.
'open' becomes 'able' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to' says to put letters next to each other (I've seen this in other clues).
'change' becomes 'edit' (edit can mean to change or alter).
'able' after 'edit' is 'EDITABLE'.
Can you help me to learn more?
(Another definition for editable that I've seen is " Subject to change".)