Yosef Karo

“ Rather, when he gets to "for every period of trouble and strife," he finishes "because you hear..." (Beit Yosef in the name of the Tosafot) . He should not change the form of the blessing. Even a person fasting individually should say "Respond to us on our fast day" (Rashb"a Siman 55) . ”

“ This is true both of an individual who has accepted an individual fast and an individual who is praying communally during a communal fast. The prayer leader who prays silently is the same as an individual in this respect and says it in "Shomea Tefila."
Rem"a: He says it prior to "Because you hear..." He does not finish the prayer with " [Blessed are You, God] who listens during a time of trouble. ”