Below is the relevant section from Turkish passenger rights https://web.shgm.gov.tr/doc4/shy-passenger.pdf

According to Arcle 9 bThey have to transport you to your final destination asap under similar conditions (conditions just means class of service - if you have an economy ticket you have to fly in economy).

But you also have the option to choose a date that suits you best - in that case availability in your booked fare bucket must be available.

So in the end - when you just want the earlier or later flight on the same day they have to rebook you free of charge as long as there are seats available in the booked class.

in case you opt for another flight date they can argue with the necessary X award bucket.

So just point out your passenger rights.