Lap Infants are not allowed in J on LA (only in Y). Call again and record what LAN's agent is telling you
. This was discussed few months ago in this forum, but you can check on Lan.com
http://www.lan.com/en_us/sitio_perso...ult/index.html
Are you traveling with a child aged under two?
Each adult can share his or her seat with a baby, paying a percentage of the fare plus boarding fees and taxes. For domestic flights within Chile, you pay only boarding fees and taxes.
If you are traveling with two babies, you will need an additional seat for their safety and must pay the fare for one child.
If the baby is traveling with an assigned seat, he or she will require a seat that is certified for use on an airplane or an ACSD safety device. Both of these items must be provided by the passenger.
Babies and children travelling in Premium Business pay the adult fare.