Erm, I'm not sure I understand your question completely, but if you're asking if you can modify the mesh in another tool after it's been exported, then no.

Today you can use solvers to do what's called mesh morphing but that's just used to implement small changes in the geometry (for example vary the angle of the windshield slightly, do some boat-tailing of the geometry etc).

If you want to modify the mesh in any significant way (run a different slant angle, change the dimensions of the wind tunnel or placement of the body) you need to do it in a proper meshing software. You should move your questions to the OpenFOAM section of the forum and their mesh generators like SnappyHexMesh or similar. This is after all the FLUENT section and not even the Meshing section.

Okay thank you scipy, that was my question ! And I'm on my way for the right topic !