Hello @Shubhangi231
If you wish to track the changes that are done a specific field (in this case the assigned to in the ci field), this can be tracked in the sys_history_line table.
Unfortunately, you can export the data in excel format, but you cannot report on this table, as this is a core system table.
The Set column indicates the record, and the Label column indicates the field that you want to check.
So checking the assigned to field changes for a ci would show like this:
