Clean a third-party component

[BrandoBrandi]

Hello everyone.
I don't have experience with Catia. I need to clean a surfce of a solid. The object is a third-party component and I don't no why but the feature recognition function doesn't work with this object. I need to remove the line on the face that can be seen in the figure. I have tried to use the Joint function but I have obtained only the yellow area in the second figure.

Can anyone give me some suggestions?

 

[MrCATIA]

The lines on the side are there because the side of the part is not smooth. To get rid of the lines, just change the Render Style to another option such as the third one (see picture).

Joining the faces, just adds a surface (yellow) on top of the solid