Conversation so far:
When dd Robbie O'Connell join the group?
1977.
Why did they decide to add him?
They asked him to take on the role Liam had vacated in the group.
Why did Liam leave?
CANNOTANSWER.
did they record an album with the new lineup?
Robbie was a songwriter, composing several numbers the group sang regularly.
Did they tour with Robbie O'Connell?
in 1977, the Clancy Brothers and Robbie O'Connell toured three months a year in March, August, and November.
Where did they tour?
CANNOTANSWER.
Did they tour elsewhere?
CANNOTANSWER.

Question: Did the addition of O'Connell change their sound or style?
Self-contained rewrite: Did the addition of O'Connell change The Clancy Brothers sound or style?