Yes, it is okay to ask for copies of these signed documents. Can I back out of it if I receive a better offer from another company?A job offer letter isn't a contract. It doesn't require a signature and, as you've experienced, a signature doesn't guarantee a job. Is it legal for them to give me an offer letter and then take it back after I have signed it. This guide describes how to apply for jobs using the Career Page web site. The process consists of the following steps: A job offer letter isn't a contract. It doesn't require a signature and, as you've experienced, a signature doesn't guarantee a job. This is a full-time position based in South San Francisco, California.