Transferring new* columns
Transfer new* columns from Excel to ArcGIS or vice versa. This operates quite fast and convenient. Nevertheless please read through the following instructions first in order for the GISconnector for Excel working exactly the way you intend it to.
"New* " in this context always means that the relevant column does not exist on its respective opposite side. In the narrower sense the column does not have to be new.
Requirement
A connection between an ArcGIS Feature Class or Table and an Excel table must be available. If you have not yet created a connection click on the button 
"Create connection" in order to establish a connection from the ArcGIS or Excel side.
"Create connection" in order to establish a connection from the ArcGIS or Excel side.
Hint:To transfer new* columns with the GISconnector from Excel to your linked ArcGIS Feature Class/Table, you have to activate this function for each data transfer direction in 
"Edit connection" in the tab "Options" once beforehand. You can define a setting in the "Default settings" for all options in “Transfer rows and columns” which will be applied for each new connection as a default configuration.
"Edit connection" in the tab "Options" once beforehand. You can define a setting in the "Default settings" for all options in “Transfer rows and columns” which will be applied for each new connection as a default configuration.Hint:The transfer of new* columns (so-called ‘schema change’) from Excel to ArcGIS will not work if ArcGIS itself has activated a so-called ‘schema lock’ on the linked Feature Class/Table. This will be the case if the Feature Class/Table is currently in an edit session, or for example has been clicked on in the catalogue window or is part of an ongoing ArcGIS Toolbox tool operation.
Read which requirements are necessary in Excel resp. in ArcGIS in order to tranfer new* columns: