Customizing a FHIR server package.

What changes are to be made while customizing a FHIR server package when adding a new field. As provided in the documentation, we have a sample JSON package of favorite color and it is added in the table, but when we are adding a new field 'Insurance', it does not imports the package and says package already exists. We have three files of JSON 

1) Package.JSON

2) SearchParameter.JSON

3) StructureDefination.JSON 

What should we have to change for adding new field.