1. Find the Proposal

Navigate to your "My Projects" page from the options at the top of the screen.

Select the "Sent Proposals" tab to find all of the proposals you've sent. You'll only be able to edit proposals that have not been responded to yet - those marked with the "Pending" status. (Those that the client has passed on will be marked "Declined," and those that have been accepted have switched to the "Work in Progress" tab.)

When you've found the banner of the Pending proposal that you want to edit, click on it to open the proposal's page.

2. Edit

The page will open to the "Proposal Sent" tab. The bottom half of the page will display the details of the proposal you've sent already. In the top-right corner of that box, you should see an "Edit" icon that looks like a blue pencil. Click that to change the proposal's details.

(If you need a reminder of what the client posted about this project originally, switch to the "Project Details" tab.)