So, I will explain my situation better: I am a Brazilian national, so I need a transit visa to UAE. I do not need a visa to TBS, though.
I ticketed JFK-IST-AUH using miles from a TK partner. So, no money involved and the ticked was issued by a partner and not TK.
My plan is to spend a day visiting AUH and then I would go do DXB and spend 2 days visiting.
To leave DXB, I redeemed miles to fly with Emirates to Zurich.
The problem then is: I cannot use travel agencies in Dubai because I will be arriving in Abu Dhabi, another emirate. The price that was charged to me was over USD 200 by the hotel, which demanded I booked a room with them for the whole 3 days. So I have to factor in the cost of transport to take me to visit Dubai in 2 different days + the taxi from AUH to the airport in DXB. This alone will cost me more than USD 400. So, not an option.
What I thought I could do was to drop the last leg (IST - AUH) and buy a ticked to TBS - which is a place I have been wanting to visit - with TK. As I will only have a carry on, I was thinking of deplaning in IST and checking in to TBS later on on the same day. The problem is the check in at JFK: if I present the ticket to TBS, will the TK agent allow me to board the plane and check me in just to IST (using the first ticket)? I do not need a visa to Turkey, either.