Sorry if this is in the wrong place!

I have booked on Etihad Airways next April to travel to Australia for a wedding. However due to circumstances I only need to use the first flight so need to re-book the second one.

Will I get fined for not showing up for the return flight?

Also, anyone know if Etihad due full refunds? If they do I'd just cancel and book on Emirates for a return flight on my specific days.

Many thanks for your help!