Field Programmable Gate Array (FPGA) technology is expected to play a key role in the development of Software Defined Radio platforms. To reduce design time required when targeting such a technology, high-level synthesis tools can be used. These tools are available in current FPGA CAD tools. In this demo, we will present the design of a FFT component for Long Term Evolution standard and its implementation on a Xilinx Virtex 6 based ML605 board. Our flexible FFT can support FFT sizes among 128, 256, 512, 1024, 1536 and 2048 to compute OFDM symbols. The FFT is specified at a high-level (i.e. in C language). Both dynamic partial reconfiguration and run-time configuration based on input control signals of the flexible FFT will be shown. These two approaches provide interesting tradeoff between reconfiguration time and area.