Lost the key of ignition switch. How can remove it?

Disconnect the battery: Before beginning any work on the electrical system of your vehicle, disconnect the battery to prevent accidental shocks or short circuits.
Remove the steering column cover: The ignition switch is located on the steering column, so you'll need to remove the cover to access it. Depending on the exact model and trim level of your Montero Sport, the cover may be held in place with screws or clips.
Remove the ignition switch: Once you have access to the ignition switch, you'll need to remove it from the steering column. This may involve removing any retaining screws or clips that are holding it in place, as well as disconnecting any electrical connectors.
Install the new ignition switch: Install the new ignition switch in the reverse order of the previous steps, making sure that it is securely fastened to the steering column and that all electrical connections are properly connected.
Test the new ignition switch: Once the new ignition switch is installed, reconnect the battery and test the switch to make sure that it is working properly. Insert the new key and try to start the engine. If the engine starts and the key can be turned smoothly, you've successfully replaced the ignition switch.
It's worth noting that depending on the specific make and model of your Montero Sport, the exact steps for replacing the ignition switch may vary slightly

You need to see a locksmith or the dealer.

take center of steering wheel off,access the star screw through a hole in the wheel to remove mechanism

the key fob? or radio remove or what?
remote to what.

the operators manual covers this , under car keys.
the car came with 2 Fobs. lost them both now>?
RKE its called, (makes looking fact more easy)
is this car with SKIS Immoblizer option> yes./no
if yes.
SENTRY KEY IMMOBILIZER SYSTEM - IF
EQUIPPED
im reading your operators guide now.
lost that too>?
Duplication of keys may
be performed at an authorized dealer (or locksmiths) or by using the
Customer Key Programming procedure.

DIY, takes 1 key , good, called a valid key, in the below text.
You can program new keys to the system if you have two
valid keys by doing the following:
1. Cut the additional Sentry Key Transponder blank(s) to
match the ignition switch lock cylinder key code.
2. Insert the first valid key into the ignition switch and
turn the ignition switch ON for at least 3 seconds but no
longer than 15 seconds. Turn the ignition switch OFF and
remove the first key.
3. Insert the second valid key and turn the ignition
switch ON within 15 seconds. After ten seconds, a chime
will sound and the SKIS indicator light will begin to
flash. Turn the ignition switch OFF and remove the
second key.
4. Insert a blank Sentry Key into the ignition switch and
turn the ignition switch ON within 60 seconds. After 10
seconds, a single chime will sound. The SKIS indicator
light will stop flashing, turn on for 3 seconds; then turn
off.
The new Sentry Key has been programmed. Repeat this
process to program up to a total of 8 keys.


did i guess right, the Key FOB RKE,
remove key entry fob.?

it is not a big deal to remove ign. switch . remove it and take to a dealer . they will make you a new key . get 3 ,and leave 2 at home where you can find them .Good Luck

Here's a guide on how to remove ignition switch.

you may want to hear this,but you may need to call a locksmith,for example:i broke my key off in my 94 Bronco at my work and needed to drive home,i had tools,but without the key you can not turn the switch to ACC in order to push the release button on the bottom of the switch(done with a paper clip),so i had to hammer on the switch until it was broken enough to turn it,the risk is damage to the column where the switch wont stay in place or will not function properly.Then a new steering column will have to be installed,fortunately i didnt damage my column.A locksmith is usually about $100.00,its sad because it only takes them about 2 minutes to remove the switch.

SOL, call a locksmith.

Why are you taking out the old one. Check with any good locksmith. If your door key fits the ignition, you can easily remove a door lock cylinder and the locksmith can make you a new key!!! I'm pretty sure to remove your lock you need to turn it with the key in it (but you don't have one)

Well,

From what I remember you need to put the missing key in and then press the cylinder release, a small hole by the ignition switch. Without the key, I guess you would need a locksmith to turn the tumbler then press the switch. Lock pick set anyone?