Q: Restoring iPhone

I have corporate phone which needs long passcode. I have messed it up and cannot remember it.

Trying to follow the support instructions, it says I can restore using iTunes. https://support.apple.com/en-us/HT204306

Connecting to iTunes and clicking Restore iPhone, it says Go to iCloud settings on my iPhone and turn off Find my iPhone.

If I could get to my iPhone, I would not need to restore it. This type of behaviour is very annoying.

Any ideas?