Yes. If it is before the deadline, you can change your bid one of two ways.
First, if there is enough time before the bid deadline, you can submit an amended bid and it will take precedence over your initial bid. You can do this as many times as necessary as time will allow, and the latest bid will be considered the final bid proposal.
The second way is to modify via fax. In order to be allowed to modify via fax, you must first call the Contracting team at (360) 902-8554 and request permission to fax modify. Once you receive permission, you must advise them of the incoming fax (that they will take to the bid opening), and then you must deposit the original modification documents at your local post office so they will be postmarked prior to the bid deadline. The fax modification is only a tentative modification until the original documents are received and the postmark verified that it was indeed submitted prior to the official bid deadline.