"In an instance" is an expression that refers to something that happens immediately or quickly. However, there are many other words and phrases that can be used to convey the same meaning, such as "instantaneously," "without delay," "in no time," "abruptly," "suddenly," "instantly," "swiftly," "promptly," "quickly," and "instantaneously." Each of these words and phrases can be used to emphasize how quickly something occurs or to describe a situation that requires an immediate response. So, whether you're writing a report, an email, or a text message, these synonyms can help you express yourself more clearly and effectively when you need to convey a sense of urgency or immediacy.