Translation:Do you want to have a discussion with the designer?
"có" is not the translation of have here. it is instead paired with "không" to form the yes/no question. in an affirmative sentence, this would become "bạn muốn thảo luận với nhà thiết kế."
if you want to have a literal translation of "want to have a discussion", you should then say something along "muốn có một cuộc thảo luận".
So I tried 'Do you want to speak with the designer?'
That's a far more likely way to ask this question in American English, but it didnt pass. I know that isn't a literal translation, but it is a fairly ubiquitous turn of phrase, and I think it should pass here. Perhaps consider it?