How would you correct the mutated cftr protein if you had the ability to tinker with it?

There several ways to attempt to correct the mutated protein. Gene therapy is possible where a virus vector is used to incorporate a corrected cftr gene into the genome. In the future, the candidate would start producing the necessary correct protein which could reverse symptoms or potentially cure the cystic fibrosis patient. Several side-effects are possible such as extreme reaction to the viral vector or the correct gene could incorporate in the wrong area causing possibly the development of cancer. Other possibilities are CRISPR-CAS9 to precisely edit the genome in the correct spot. The downside is that this makes a permanent alteration in a person's DNA that could be passed on to offspring while the gene therapy would not.