Can an order be filled but uncommitted?

External question — Quantitative Finance Stack Exchange Author: user20804 Original post: https://quant.stackexchange.com/questions/26130 License: CC BY-SA 3.0 — https://creativecommons.org/licenses/by-sa/3.0/ Adaptation: HTML converted to plain text; contact email addresses removed. Let's say I place an order to buy shares. Let's says uncommitted shares are those not actively working with other destinations or brokers, and committed shares are those actively working but yet unfilled with other destinations or brokers. Can my order be filled and yet uncommitted? If yes, how?