You can transfer your Citi Thank You rewards to participating travel loyalty programs. One transferee is JetBlue TrueBlue. Citi Thank You rewards transfer to TrueBlue points at a rate of 2:1, so 1,000 Thank You points would yield 500 TrueBlue points.
There is currently a limited time offer through October 25, 2017, where you can transfer ThankYou Points to TrueBlue and receive 25% bonus TrueBlue points. So now you will get 625 TrueBlue points when you transfer in 1,000 Thank You points.