I checked right through 31st, economy looks closed throughout.
There are couple J seats here and there.

I doubt you could change your reservation to the dates you wanted, unless:
- You are a skywards gold member; and
- hold a flexible fare ticket ( I think M and above - could be just W/Y)

Check the fare conditions on your tickets for that sort for changes etc. Usually they don't charge for change of dates; As for the way to do it, just give Emirates a call.

Cheers