Lumia Denim prepI just did this on my Lumia 1020 (India, developers preview enrolled) and it worked. So here is what you can do in case you have Lumia Denim available for your devices as per the official tracker but, you are not able to get it due to enrollment to developers preview program.

Just opt out of the developers preview program—-> restart you device——> Check for updates.

Keep in mind that since a new OS version 8.10.14234.375 is available for Lumia 1020 in India as part of Lumia Denim update, you are being offered an update. If you are already on OS version 8.10.14219.341 (developers preview) and the tracker shows similar OS version available for you device under Lumia Denim, you may not be offered an update at all, as all the devices except Lumia 830, Lumia 930, Lumia 1520 and Lumia Icon won’t mostly receive any firmware update with Lumia Denim.

8.10.14234Try this and do let us know if it worked for you too.