The link RedPhantom provided in his comment is for converting conforming clothing between different figures.  

@ drawn: If you are interested in converting dynamic clothing between LF and LF2, then this is not the process you want to be using.  Dynamic clothing conversion between these 2 models has been simplified with the Prefit Tools that are packaged with La Femme 2 Pro which you own.  These tools can be found in the Props Category of the Poser Library.  Load the dynamic clothing item into your scene and then load the appropriate tool for conversion.  At this stage, a simple copy morphs from the tool to the clothing is all you need to do.  If you are not familiar with this process, don't be shy to ask.  Afterwards, you can run your Cloth Room simulations.  Again, if you do not understand how to use all the features of the Cloth Room, please ask with as much information you can provide.

Conforming clothes conversion is more involved and complicated.