For at least one scene, she apparently took the place of what was originally planned to be Plutarch due to the death of Philip Seymour Hoffman. From Nina Nina Jacobson's answer to this Quora question ([*How did the tragic death of Philip Seymour Hoffman alter the Hunger Games franchise?*][1]):

>  Practically, Phil had shot about 80% of his scenes.  What we had to
> do with the remaining 20% was to give two key scenes to Liz Banks and
> Woody Harrelson.  In MJ1, Effie gives Katniss Cinna's design for the
> mockingly uniform instead of Plutarch, as was originally scripted.  In
> MJ2, Haymitch reads a letter in a scene that, in the book and the
> original script, takes places between Katniss and Plutarch.  Without a
> doubt, Phil would be a bigger presence in the movie if he had stayed
> with us.

Once this decision was made, it makes sense that she would also play the part of a stylist in subsequent scenes.

I came across this quotation by reading Roger's answer to this question from Movies SE: [What changes to Mockingjay Part 2 were made due to P. S. Hoffman's passing?](http://movies.stackexchange.com/questions/44151/what-changes-to-mockingjay-part-2-were-made-due-to-p-s-hoffmans-passing/44161#44161)


  [1]: https://www.quora.com/How-did-the-tragic-death-of-Philip-Seymour-Hoffman-alter-the-Hunger-Games-franchise?no_redirect=1