you would like to chat with people who is in DND mode ???
He or She must be someone you know, a friend right ??? and that's why you got this nick in your buddy list.
no one can chat with DND User, but you can let him know that you wanna chat with him or her.

first way : go to the room where he or she is chatting, just rightclick on her or his nick and NUDGE him or her he or she will get you PM windows

second way : add her or his nick and OPEN his or her room,
no matter right or wrong code, they will get a message of Paltalk