Best way is hardware, also the fastest. Find a post house with an Alchemist PhC HD.
Slower less good looking way is software. Drop it in compressor and enable best quality motion compensated conversion. This will introduce a lot of problems, but will kinda look okay if you don’t watch too closely. It’s sllllloooooowwwwwwww, but free. Slow as in 20-30:1 ratio.