If you fly to any countries you will not have any problems switching passports and applying for a visa.

What about it??

When did you do this Kurt...?? Security and use of 2 passports has tightened up considerably in 2017. I tried in January 18 and was told that I can't do it so it has changed. It doesn't matter what you have done for the past 20 years....laws do change on occasions.

Man I have a headache....So what I can understand is that she got a single entry 90 day visa that she has already used by entering Thailand. She now goes to immigration and prepares all of the documents required for a year extension and applies for that a min of 21 days (more is advised) . If she needs to exit the country at any time during the 90 days (or the year extension) she will need to apply for a RE-entry permit from immigration or at the airport.

Ewelina looks like your question is answered. Fly to Laos. Switch passports on the plane. Use that one for the new visa.

Passport 1

I also have 2 passports and have swapped passports many times by air and at borders....but you can't do it at Thai borders specifically....I went last month and tried it...Cannot...!!

Yes but you can't swap them at the border while doing a border bounce as the exit stamp, cambo visa and entry stamp must be in the same passport.. Which is what this thread is about.

Yes I have 2 passports. Can't swap at a Thai border if border bouncing. Can send a 2nd passport for a visa while here though.

1 reason is that you can double the life of 2 passports instead of using one all the time.