Hello I have a Roan classic stroller. I want to make it a two passenger. Is that possible?
Unfortunately, no. The only way would be to attach a buggy board for an older sibling though with that classic, rocking frame, many will not fit right. Try the Bumprider or Lascal Buggy Board Maxi (theoretically with a seat), though try it in a shop first as the attachment system might fit weirdly.
Other than that, the stroller cannot be converted into a sibling stroller, no.