Hi,
if the dead reed switch is stuck open and easy to gain access to, you can consider not melting the contacts on the PCB side (which can be tricky), to replace it.
Instead, keep the dead switch as is, and soft-solder the new switch aside (parallel connection), using the dead switch arms as solding points.
It is what I did to successfully and easily fix my Conchess device.
MfG,
Tibono