I have a cordless phone with a LCD that has some of the characters
missing. I was able to determine it is a poor connection at the point
which a flex ribbon cable is attached to the PWB. That connection is
apparently soldered with the infrared technique. Does anyone have any
ideas on how such a connection could be repaired with common electronic
repair tools?

Obviously it can be done with the tools used to assemble the circuit
when made, but not many people have such tools in their homes. Thanks.