Just now, Bayushi Shunsuke said:

Bayushi Liar has a Spyglass attached. (" After attached character commits...")
Or an Ancient Master attached ("After attached character is declared as an attacker or defender...")

Bayushi Liar attacks politically into a Rally to the Cause.
The defender is First Player, and uses their first reaction to change conflict type.

Bayushi Liar goes home bowed.

Can the attacking player, as second player, trigger a Reaction to attacking if the character is no longer participating due to the first player's reaction?

Yes, Liar was declared as an attacker and can still trigger Spyglass even though it’s been moved home.

[Tyler Parrott: November 14, 2018]