You can Relist your Listing if it is:
Simply login to your account, select the appropriate Listing in 'My Listings' and click the RELIST action button.
This will create a new, identical Listing for Providers to Quote on. Unfortunately, if you had any previous active Quotes, they will not be valid. However, you can use the Invite Provider feature to notify Providers that you would like a new Quote.
If you wish to make changes to your Listing before activating, use the List Similar feature instead.