  Coronal mass ejections (CMEs) are one of the primary manifestations of solar
activity and can drive severe space weather effects. Therefore, it is vital to
work towards being able to predict their occurrence. However, many aspects of
CME formation and eruption remain unclear, including whether magnetic flux
ropes are present before the onset of eruption and the key mechanisms that
cause CMEs to occur. In this work, the pre-eruptive coronal configuration of an
active region that produced an interplanetary CME with a clear magnetic flux
rope structure at 1 AU is studied. A forward-S sigmoid appears in
extreme-ultraviolet (EUV) data two hours before the onset of the eruption
(SOL2012-06-14), which is interpreted as a signature of a right-handed flux
rope that formed prior to the eruption. Flare ribbons and EUV dimmings are used
to infer the locations of the flux rope footpoints. These locations, together
with observations of the global magnetic flux distribution, indicate that an
interaction between newly emerged magnetic flux and pre-existing sunspot field
in the days prior to the eruption may have enabled the coronal flux rope to
form via tether-cutting-like reconnection. Composition analysis suggests that
the flux rope had a coronal plasma composition, supporting our interpretation
that the flux rope formed via magnetic reconnection in the corona. Once formed,
the flux rope remained stable for 2 hours before erupting as a CME.
