Error correction performance of finite-length polar codes has been a major concern in the past decade. This Letter presents a method for improving the error correction performance of cyclic redundancy check (CRC)-aided successive cancellation list decoding for polar codes of medium block-lengths with high code rates. In the proposed decoding scheme, a one-time repetition of least reliable bit-channels along with partial protection of the message is employed to correct the error(s) when decoding fails. The results show an improvement of nearly 0.2 dB in error correction performance.