搭讪 (搭訕) dā​shàn
break silence verb
to start talking in order to end an awkward silence or ease an embarrassing situation

Since the atmosphere was so awkward, he quickly struck up a conversation to distract everyone.

strike up conversation verb
to initiate a conversation with someone, often with the intent of flirting or making an acquaintance

He took the initiative to strike up a conversation with that girl in the bookstore.