A ServiceNow Admin or user should not change or rename column or field names. There are several scripts and other platform logic that refers to the original field name of when the field was created. If the field or column name is changed, this can cause unexpected errors as it will not be pulling the correct reference.

Workaround: 

There may be cases where the admin or user wants to make an edit to the column or field. In this case, the user or admin can first export the column or field data and then delete and recreate a new column or field. This KB explains the steps to exporting columns using XML: KB0610525 . This way, the references will not get affected by any changes. 

Another workaround would be to change the Column Label. The change to the Column Label is only a cosmetic change and will not affect any of the reference names. 

Example:

Please refer to this KB article when exporting columns on a table: Export all or specific columns using XML.

KB0610525