M.K. Williams | Do I need a new ISBN if I want to change my subtitle? #selfpublishing #isbn #amazonkdp @1MKWilliams | Uploaded June 2023 | Updated October 2024, 6 hours ago.
In this case for changing your subtitle... you need a new ISBN.
Amazon KDP, IngramSpark, and other self-publishing platforms don't let you change the title or subtitle after you hit publish.
(*If you just hit publish in the last week and noticed a typo in the title you MAY be able to write customer service and beg and plead for a correction, I've seen them be lenient with brand new authors before).
If you absolutely have to change the subtitle, you should do so, but you may not be able to port over your current reviews as Amazon KDP requires the title (and subtitle) to be the same in order for reviews to connect between editions.

More on Second Editions
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More on Uploading to Amazon KDP
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