I expect it would be a matter of providing documentary evidence of the name change to the managing agent and asking for the change to be made.
However, I wonder why anyone bothers with this woman-has-to-change-her-name thing these days. I have been happily married for 27 years but my wife still has the name she had when I met her. I expect your wife has all sorts of things with her name on them: documents, licences, qualifications, job references, certificates, authorship of publications, titles to property, bank, superannuation and other investment accounts, and so on that would be a pain to change. Why not leave all that as it is?