Problem with Mirror part in assembly

[miguel_amf]

Hello! first, sorry for my english, im having problem mirroing a part(surface) in assembly, i cant edit the object anymore. Every button is grayed, im missing something but dont know what it is.

Heres a Pic

 

[MrCATIA]

Hello Miguel, (your english is pretty good)

Although you have an Assembly open in your CATIA session, the Copy of Ala Part is active and you are in the Part Design Workbench.

If you want to mirror the Surface into the same part, change to the Generative Shape Design workbench and use the Symmetry tool there.

Also, since you are in Hybrid Design mode, make the PartBody be the Work Object before you mirror the surface.