Change ArticleFreeText values in existing articles

[Flogo]

Hi,
is it possible to change ArticleFreeTexts once the article exists? I was able to set it up, so that I could enter a value when adding a note, but I'm not able to change that value or add a value to notes that I created before.
What I'm trying to do is to add a information about the time it took to solve this part of the ticket. I don't want to use TicketFreeText, as the Ticket could be solved in stages.

Thanks for your input,
Flo