I'm a newcomer to fountain pens and I want to convert a Visconti Opera FP to use the ink cartridges. I'm sure the answer is here somewhere. Thanks for your advice. I look forward to my fountain pen education.

Have you tried removing the converter by pulling on it gently, and then replacing the converter with a cartridge?

Thanks for the advice. Given the price of the pen, I was hesitant to start tugging on things. But that worked perfectly!