I changed my mind after accepting a job offer. What are consequences?

I am working in (Company A), I recently signed a MOL job offer letter from a company (Company B) in Dubai, however, I have since been offered another job which I wish to accept from Company C.

Is it possible for me to withdraw from the original offer letter from Company B and sign with Company C?

Note: I am still on employment visa from Company A.

Does this affect the employee withdrawing from the offer? Will I still be able to accept the offer of Company C?

Any help would be greatly appreciated.

Thank you!