Chloebware , the Judge is the only person who can cancel the shares of any Chaptered company . I will take a guess that Delta's and K-Mart's shares were in the hundreds of millions or billions which would have been burdensome to the survival of those two entities and the protection of the creditors .
Creditors get the new equity as their surety , and the retention of the common would have diluted that surety , therefore the common were cancelled in those two companies and any other company in a similar situation of debt exceeding assets .
It appears much different in LandAmerica's situation where it appears the assets exceed the liabilities .