Hello Arielle. Welcome to the forum.
Most IGES files are surfaces. It could also be that the file was actually a facet file. You cannot manipulate facet files but the Import Data Doctor can do limited modifications to surfaces. You can also act on surface "quilts" using Creo features.
It you simply need a 2D file in Creo, you have other options, such as making a drawing view and saving it as DXF.
If you can post an image of what you want to achieve, we might be able to help more specifically.
