Outstation

Where is Miszsensei? I haven't seen her for the past few days..

Owwhh.. she is outstation

That's the common usage of 'outstation' in our country and that is not how we convey the message that the person is actually out of town. So, let's see the explanation I got from Mind Our English - The Star

The word “outstation” is not used in modern standard English to mean “out of town” or “out of the capital city”, although some Malaysians use it to mean that. It was a British colonial word, when there were still main trading stations and outstations, which is defined by the OED as “a station at a distance from headquarters or from the centre of population or business.”

The modern meaning of outstation (outside Australia and New Zealand) is “a branch of an organisation situated far from its headquarters.” (Concise OED 2009)