WikiTree is a collaborative genealogy site, with one profile for each individual. What this means is that is you and Jo have the same indiviual in your trees, you should be work together to get the correct information on the profile. Just noting that information is incorrect is not enough.
Perhaps the best way to deal with differing information is to post a message in the Public Bulletin Board box on the profile showing what information you have and what your sources are. Then, if the profile manager has sources for her information, she can post it there or send it to you in a private message. If she has no sources and you do, she may be willing to change the info on the profile. If she has sources too, you can try to work it out between yourselves, and, if you can't, post a message on G2G to see if someone else can offer more info or sources.