Hello and thanks for reaching out!
To unlock the tablet, you will have to go to Verizon for assistance. I also suggest consulting with the service provider in Singapore to see if there is 4G capabilities.
If you need additional assistance please contact us again. You can also reach out to us via twitter or facebook for quicker responses.
Thank you and have a great day!
Samsung Mobile Support is now available on Twitter & Facebook!
Chat Support: http://goo.gl/ZALJm