How long does it usually take a patent agent to modify a document?

According to my experience, after submitting complete technical disclosure materials to the agent and fully communicating,

The writing time of the first draft of the agent is generally about 2 weeks.

After that, the text written by the agent will be reviewed.

Put forward amendments, and generally give feedback in 2-3 days for non-major changes.

Your situation is really depressing. You can contact the agent to confirm it.

If you don't get a response, you can complain.