The application itself is quite straight-forward. Similar to the form we fill for BLS (we did it for my spouse in Canada). But there's no checklist for supporting documents. I called the customer service twice. Got different answers each time. One even said all you need is the proof of citizenship and original Indian passport. It's a good idea to refer to the BLS checklist and take all documents that apply. However the documents I submitted are: Application form, Citizenship certificate, Original and 1 photocopy of Indian and Canadian passport, Proof of current Indian address. Apart from this they gave me a form which I had to fill and also asked to write an application letter. I did carry a photograph. But they clicked one at the centre when they took biometrics. They canceled my Indian passport and returned it back to me. They scanned all the other documents and uploaded it in their portal. I got the surrender certificate after half an hour.
Fees for surrender is Rs. 500.
Finally the first question. You should call the customer service and check for which RPOs offer the service. Bangalore has 3 passport offices. Surrender certificate service is available only at Koramangala office. The customer service said that you don't need appointment for surrender and you can walk-in. I had heard there's a line up and went at 8:30. But it was not required. Office opens at 9:30. The line up is once you go to the concerned department. I handed my application to them at 10:10 am and walked out with the certificate at 4:45pm! I don't know why it took so long. There was no apparent problem with my application except they asked me for one more proof of address which I submitted soon after I gave them the application. They deal with a lot of other passport related services, which is probably why it took them so long. Once I was called in for biometrics (at 4:15pm) it took 20-30 min to receive the certificate and cancelled passport.