It really depends on your OTA. Some people were successful in doing these kinds of changes, some others were receiving generic copy-paste answers from their OTA.
Worst case scenario, I'll be prepared for a lengthy talk.

UPDATES AS 22 DECEMBER TO THE GUIDE POSTS:

The following have been indicated into the respective posts
1- Turkish Airlines have extended their zero-change fee policy for new reservations made up till 31 March 2022.
2- 115% valuable travel vouchers could now be used through the hotline and through the TK website.

I requested today the conversion of a ticket value into miles. I got a penalty document in my mail right after the transaction confirming it. However, I haven’t gotten the miles deposited in the account yet. It’s been 8h since the call. Is it normal? Any idea on how long does it take?

A penalty document? Why should you be penalized for converting your ticket value to miles? :rolleyes:
Normally, it could take up to 2-3 business days ( 25 Dec counts as a business day in Turkey ) for those miles to be credited to your account.

The subject of the mail I received was ‘Turkish Airlines Penalty Document’, even though the information that it contains makes sense 🤷🏻‍♂️. I was thinking of booking a ticket today but it seems that I’ll have to be a bit more patient. Thank you for the info ISTFlyer ! Very helpful, as always!! :)

I have a UK to Seychelles trip in 3 months. Currently the UK has banned us flying to Seychelles and Seychelles has banned UK citizens.
IF the situation is still the same (highly likely) and we are not allowed to travel but the TK flights are still going, I assume I can only move the flight till Dec 2021 but will have to pay the fare difference, unless TK cancel the flights?

You would be able to rebook your flight until 31 December 2021 without change fees and the travel date does not matter.
To able to rebook beyond your ticket validity, you would need to convert your ticket to an open ticket and use it by 31 December 2021 whenever you decide to fly.
Obviously, the fare difference would apply in both cases if the situation is not involuntary.

Thanks ISTFlyer.

You're welcome :)

If I want to change the origin of a Star award booking but it stays within the same region, is that considered a complimentary change or would a cancel (with a fee) and rebook be required? In this case, I’m looking to change OGG-LAX to HNL-LAX.

Complimentary. However, a reminder that on some occasions, the hotline might not perform a destination change on *A awards and they might suggest to cancel your old ticket and purchase another one; in this case, they are unable to waive the $25 cancellation fee. In order to avoid this issue, your best bet is to contact a sales ( ticketing ) office and ask the agents over there to perform the change. It's not possible to do this change online.

What to do?
 

I don't even know where to begin with this.

I have (had) 4 J class rt ATL-IST-BER (original price a little over 10k) leaving in March coming back mid April.

Because of Covid-19 I emailed our local (ATL) office and requested a change to October 3 - October 22, 2021.

As I hadn't heard back from them I decided to look on the app and see if their technology had improved where I could change it myself. lo and behold it let me change the dates, and even offered me a very small (about $45) refund.

I want to make this perfectly clear that nowhere, and I've gone back and duplicated the change efforts, does it ask about what class of service did I want. I had J class, and ONLY changed the dates. It may be different on the actual computer website, but in the app it doesn't.

I made the changes and by chance was looking at the email confirmation and it shows all 4 tickets in economy. Two phone calls to the US TK # got nothing but a too bad so sad and the local office hasn't answered any emails and I rung over 50 x's and never an answer.

Suggestions?

I priced their most expensive economy tickets for those same dates and it only comes to half of what I have already paid and they want $2900 to put me back in J.

Thanks

CJ

You could visit the local office in person. A much more effective method as they wouldn't be turning you back from the door.
Also, if there is availability on the same fare basis that you originally paid, you could always pay the $45 fare difference and upgrade it back to J.

If the app didn't waive the change fee and charged it according to the original fare rules and then it calculated the $45 refund, unfortunately, your situation would be complicated and I strongly advise you to visit a sales office in person. Filling multiple feedback forms might work, however, speaking with a person face-to-face ( even with masks on ) would be more effective.

Thanks as always ISTFlyer

You're welcome :)
Please don't forget to report your experience after you solve it.