If you need to transition labs, for whatever reason (research interests changed, personalities aren't jiving, etc.), there are some things that you should do.
1a) See your the head graduate advisor (currently Claire Kremen) first and let them know what you are thinking of.
1b) Talk to your guiding professor, but this might be awkward given the particular situation, so...
2) Speak with your new guiding professor.
3) Go and see Doty to get the paperwork. You will need to fill out a form for a "Change in Dissertation Committee". There might be other small logistics, such as funding/appointment issues that need to be sorted out.

Sometimes there are lab switches that are "hostile". While it's yucky, these things happen. In these cases you should ask the Head Graduate Advisor what course to take. If things get really messy (data access issues, intellectual property, etc.) there is an on-campus Ombuds that you can see and you will most likely need to meet with your Division Chair and with the Departmental Chair.