If you have central heat/ac your thermostat might have a switch to convert it from 'auto' to 'on'. You can combine that with turning off the heat/cooling such that it's just a house/apartment-wide fan. I do that at night before going to bed to deal with poor airflow in my bedroom and according to my CO2 sensor, it works. It works correctly even if I leave it set to cool or heat, the thermostat still controls whether it's actually heating or circulating air. Likely what you have is the same.