I've always held the position that Acts 20:7 states "when the disciples came together to break bread." But in my recent study, I've realized the Greek is actually Strong's 1473, ημων - "we." How is it, then, concluded that there was a church at Troas? I am not aware of any specific mention of such. This passage doesn't say "the disciples" of Troas, but only "we." It seems an assumption, not an unavoidable conclusion that there was a church in Troas before this event.
There is a textual variation in this spot in Acts 20:7. Texts 020L, 025P and the Byzantine family of texts all say "the disciples", while texts 01א, 02A, 03B, 05D, 08E say "us." Here I'm inclined to think the Byzantine family is closer to being accurate because otherwise we have pronouns being used without a noun clarify who is being discussed. But rather than getting into an argument about which text is right, let us assume for the time that it is just "we" and examine the context for who the "we" is.
Luke typically uses "we" when he and others are traveling with Paul, such as Acts 20:13. But there is more than just the "we," both Acts 20:6 and Acts 20:7 mentions "them." There was a group of people that Paul and his companions came to meet. It was this same group that they gathered together with on the first day of the week for the purpose of breaking bread and to deliver a message.
"Gather together" should not be overlooked. "For, in the first place, when you come together as a church, I hear that divisions exist among you; and in part I believe it. For there must also be factions among you, so that those who are approved may become evident among you. Therefore when you meet together, it is not to eat the Lord's Supper" (I Corinthians 16:18-20). This is what we see in Acts 20:7, a group of people come together to break bread. See: Is Acts 20:7 talking of a common meal? for reasons why "break bread" here is referring to the Lord's Supper.
Thus, we conclude that "them" refers to a local church and the understanding of the text doesn't change with the absence of "the disciples" in Acts 20:7.