Yes, if the defendant doesn't accept an offer the DA can withdraw it, and make a higher offer. However, if the DA's offer is life, there's nothing to lose in going before the judge without a recommendation.
Without knowing more that we can get into on avvo, I cannot comment on the issue of "personal reasons". I suggest that your friend needs to discuss that with his or her attorney.
As far as the authority to change a plea offer from 25 years to life, as a practical matter, a prosecutor has the power to change the offer until it is accepted and done in court.
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