Use case
Return the display name of the previous reporter.
Expression
Create and configure a Smart field using this expression in Jira Expression parsing mode:
let reporters= issue.changelogs.map(i=>i.items).flatten().filter(i=>i.field=="reporter"); reporters.length>0 ? reporters.map(a=>a.fromString)[0] == null ? "" :reporters.map(a=>a.fromString)[0] : ""