Brown, dying stem. Rest of plant seems fine?

[RosieC]

It's nothing to worry about. The flower stem will often die back, as help has said the sometimes rebloom but not always.

Now it's died back just cut it off close to where it joins the plant (as close as you can without damaging the plant). I actually cut most of mine back even before the stem dies.

Carry on caring for the plant and eventually a new flower stem will grow. Many phals will produce a new spike in the fall after a drop in temperatures, mine have produced them this spring because the temp drop was too much as they went dormant over the winter. Other phals respond to light levels, in the summer and start spiking then. It's difficult to tell which a particlar plant will respond to, but the majority of hybrids from a supermarket will be temperature dependent.