Comparing values in automation between two issues

[Joe Harmon]

I have two issues in jira that are linked through an issue link.  I want to be able to use jira automation to detect when a change happens to a field.  For example, let's say I have a field called due date.  When the field changes for a specific issue type, I to compare that field with the issue it is linked to, and if the date is later than the issue it is linked to, I want to copy that value to the issue it is linked to.

[John Funk]

Hi Joe,

You should be able to do that using Automation for Jira - probably ScriptRunner, too, I just don't know the latter tool. Do you have either one of those add-on apps?