I live in Bangalore. I need to change the old passport number to new passport number in Singapore visa? Tomorrow I will receive my passport and my travel date to Singapore is on 15april.
You have to obtain a new visa. From my experience, it can take from a couple of days to one week. So, just rush for that. Alternatively, if a Singapore citizen or PR can vouch for you, they can apply the visa online and it will take only one day or less.
From the Singapore ICA website,
Q13: How do I transfer my valid visa issued on my old travel document to the new one?
A: You must obtain a new visa if you are intending to travel to Singapore with a different travel document from the one submitted during the application for this visa You should obtain the new visa before travelling to Singapore. You may approach the nearest Singapore Overseas Mission or through the authorized visa agents of the Overseas Missions for the details. Basic supporting documents require from you are : old and new travel document (original and copy), the valid visa, Form 14A duly completed and signed, photograph. The photograph should be a recent passport-sized colour photograph taken within the last 3 months and must be taken against a white background with a matt or semi-matt finish.