You can edit your bid response at any time up until the due date and time of the bid. You can do this by clicking into the bid and clicking on the More Actions menu on the top right and selecting Edit Quote. Make any necessary updates to your quote and when you are finished click on the Publish tab and press the Finish button to submit the new information to your customer.
See the articles below for additional information on Bid Requests:
Joining and Accepting a Bid Request
Bid Request - Confirming Bid has Been Submitted
Submitting Bid Questions & Messages