If you lose your job in Singapore while on an Employment Pass (EP), your EP will be cancelled immediately. You will then have 30 days to either find a new job and have your new employer apply for a new EP for you, or to leave Singapore. In other words, you will not be allowed to stay in Singapore without a valid EP for more than 30 days after your job loss. You'll have 30 days to secure a new job and reapply for an EP else you will need to leave Singapore. You will be able to return to Singapore if you are able to secure a new job and obtain a new EP.