The phrase "a postscript to an" is correct and usable in written English.
It can be used when referring to an additional remark or note added after the main content, often in letters or documents.
Example: "In a postscript to an earlier letter, she clarified her position on the matter."
Alternatives: "an addendum to an" or "a note following an".
It was not so much a postscript to a career as a promise for his future.
In a postscript to a long essay on photography, he recounts a safari during which he snapped a picture of an angry lion.
Mr. Eikenberry's comments, in a postscript to a speech in front of about 200 students and faculty members at Herat University, departed sharply from the normally tolerant public stance that Western diplomats had taken with Mr. Karzai.
In "A Postscript to a Sociological Utopian" (1989), he wrote, "In C. Wright Mills I was dealing with a sadly flawed individual, a human being who had biased attitudes on many issues, including minorities, Jews, women, and especially blacks".
The word is used as a postscript to a stupid action or statement; it is probably a bastardisation, of the kind that the internet tends to produce, of "duh".
Mariyan Ognyanov's 89th-minute goal in the national stadium was well taken, drilled clinically past Petr Cech from a high, bouncing ball down the middle, but was very much a postscript to a Didier Drogba hat-trick.
As a postscript to a program notable for its stinging relevance and steadfast humanism, "Mavis!" aptly summed up a timely and cathartic weekend, sending its audience on to the muggy D.C. streets on mighty clouds of pure joy.
The big news is that a major museum has quietly taken a firm stand on modern art in Asia, seeing it not as a postscript to a great tradition but as an integral, living part of the continuum.
Two weeks later, Johnson pre-empted greater popular rejection and astonished the nation by suddenly announcing in a postscript to a televised speech that he would not seek re-election and would devote his energies to ending the war.
