Need to update reference field by using background script

[Arun91]

Hi Team,

I have a field called location in cmdb_ci table which is OOTB. I have created a custom table and create a field in cmdb_ci referencing to custom table. Based on the OOTB location field need to update custom reference field in servicenow. How we can achieve through background script in servicenow

[Arun91]

We are retrieving from Third Party tool. If we have two branch address with same name but branch code is different. In this case how we can execute the background script. Could you please help on this.