You have quite a lot of drawing with title blocks name "AP01243-A1".
In that title block, there are attribute tags "JOB1", "JOB2", "DWG1", "DWG2", and you want to change them to "TITLE_LINE_1", "TITLE_LINE_2", "TITLE_LINE_3" and "TITLE_LINE_4".
There are two types of attribute object: the attribute definition and the attribute reference.
The attribute definition is created by ATTDEF command. It is included in the selection when you run BLOCK command to the block definition
Then, you insert the block via INSERT command. The attribute reference is created in the background. It shows up in the inserted block's properties or the EATTEDIT window. It is an object attached to the inserted block.
When you explode the inserted block, you got back the attribute definition object, not the attribute reference object. The attribute reference object never shows up as an independent object that users can select. It always shows up as a property of the inserted block.