Cannot remove node after aspect property change

[goldfiled]

Hi,
    I define my own model, which has an aspect and its property is String, then I create content use this type,
after that I change the model file,  the property type from String to List,  then I can't remove node !!
the log is:
org.alfresco.service.cmr.repository.datatype.TypeConversionException: There is no conversion registered for the value:
   value class: java.util.ArrayList
   to class: java.lang.String
   value: [AI, AIB]
        at org.alfresco.service.cmr.repository.datatype.TypeConverter.convert(TypeConverter.java:113)
        at org.alfresco.repo.webservice.Utils.createNamedValue(Utils.java:239)

How can I remove the node without modifying that model file?
I use Alfresco version: 3.2 community

Thanks in advance.

[sselvan]

I believe you will have to remove the related content or disassociate the related content type of those contents.
Then only you will be able to proceed.

Though I am trying to propose a solution, I don't think this is the best way.
You might want to wait for others user also to suggest a solution (or an official alfresco response).