If you want to move records from a parent table to a child table, that should be relatively easy to do. Each table has a field by the name of "sys_class_name" which describes which table the record belongs to. For the records in the parent table, you just change the "sys_class_name" field from "change_request" to your new table name (eg. u_my_change_request).
If you wish to do this for all of the change_request records you have in that table, you simply do a GlideRecord script that queries all of the change_request records and sets the sys_class_name to the new name and updates the record.
This works in this scenario because you are moving records from a parent table to its child table, thus you know all of the field will exist in the destination table.