No, you can't transform the list with comment into another type of question.
What I would do is to add a open ended text question after the multiple choice question and format it via Javascript/CSS so that it fits best to the layout you want.
Help us to help you!
Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).
Note: I answer at this forum in my spare time, I'm not a LimeSurvey GmbH employee.
