unable to unbend cone feature

Hello,

For a assignment i have for school i have to make a cone feature with a cilindrycal cut-out in the cone feature.

Now i have created the cone feature in de sheetmetal module with a lofted-bend but now I'm unable to unbend the feature.

Has someone a solution to this problem ?

Thanks in advance,

Greetings Peter

SolidworksSheet Metal