changing saved DS-156

[elephant]

By mistake I specified 'Nationality' filed in my mother DS-156 application as 'Indoneasia' it should be 'India'
how can i change that to india.
when i am trying to retreive/modify the application form ....this field is coming as disabled field and not allowing me to update the nationality
please help me how can i modify this in the save application ds-156.

[immihelp]

If that field is disabled, you can't change it unfortunately.