If you are a Secondary 4 student who is 19 years old and below, you CAN defer NS for ITE / Polytechnics.
If you are a Secondary 5 student who is 20 years old and below, you CAN defer NS for ITE / Polytechnics.
Now that is assuming your friend is in secondary school. If he is in ITE and you are asking about ITE to Polytechnic, the cut off age is 21 years old for both Nitec and Higher Nitec Students.
For everyone else, it depends on a case by case basis.
No you don't need to physically go down to CMPB. Simply call CMPB at 1800-367-6767. State your NRIC, Inform the phone operator that you wish to defer for further studies.
The phone operator will then ask you to get a OFFICIAL ENROLLMENT COURSE letter and either FAX it to them at 6853-7894 OR scan the document and attach a JPEG file email and send it to
contact@ns.sg
If you do not have a enrollment letter ( everyone should get it weeks before their school starts ), you can simply go down to your ITE help office or Polytechnic student service and request for one.
Any other questions feel free to ask... But if you want a quick response, I strongly suggest you call NS Helpline or CMPB hotline.