CORE will allow you to create a new version of a Solicitation to make changes if the Solicitation is still open. However, the following error will appear if you attempt to edit a closed Solicitation:

The system will not allow Solicitations that are closed to be changed, as the information contained in the Solicitation should be available to all vendors prior to the solicitation response deadline. Therefore, if a Solicitation close date must be extended, an attachment attached, or other edits need to be made, do so before the Solicitation is closed.