I have an old project with AVCHD clips and I want to import the clips again with surround sound. How can I relink the project clips to the re-imported ones without doing the project from the begining?

I have an old project with AVCHD clips and I want to import the clips again with surround sound. How can I relink the project clips to the re-imported ones without doing the project from the begining?

I have a sony handicam and I imported the clips to iMovie and they lost quality and converted the audio to stereo. I want to import the project to final cut X and import the AVCHD in 1080p and surround sound and export the movie in bluray. Can I relink the clips without editing everything again?

thanks!