You can transfer your Citi Thank You rewards points 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 May 19, 2018, where you can transfer ThankYou points to TrueBlue and receive 30% bonus TrueBlue points. So now you will get 650 TrueBlue points when you transfer in 1,000 Thank You points.