Choosing between 2 job offers

What is the name of your state?What is the name of your state? CA

An unusual situation came up during a job search. Received a job offer
with 1 week to make a decision. After accepting the offer, learnt that
there is a second offer (from another company) forthcoming in
a short time, prior to starting the first job.

Question: What happens if you change your mind and accept another
offer, before you have started at the first co? What if any liability
(beyond an ethical dilemma) exist?

This person works in a "regular" (non-executive) job in
the high-tech industry; there is no signed contract. However the
first position involved a (company-paid) search firm.

There is no liability at all. You are at liberty to change your mind and accept the second offer, when and if it comes through. Nothing in the law is going to force you to go to work for the first company.

It may or may not affect your credibility with the recruiting firm, depending on the exact circumstances. But slavery and indentured servitude have been illegal in this country for quite some time. In the absence of a contract, you have no legal obligation to work for anyone you don't want to.

(In fact, even if a contract DOES exist, you can break the contract if you are willing to put up with whatever conditions the contract places on you for breeching it.)

thanks!

appreciate the quick response, and glad to know there is no liability.
the offer letter only mentions the usual clauses i.e. at-will, exclusive
employment, non-disclosure etc so it should work out ok.