If you want to make edits to a template after you have queued a campaign, you can do so unless that template has begun Processing. Core iQ will always check for the most recent version of the template when it begins Processing items to leave the system. This means that any edits you make to the template between the time the campaign is finalized and when it begins Processing, will be reflected on the outbound items. So if you see a typo shortly after you queue a campaign, don't worry. Simply make the changes to your template and ensure that it is reactivated. Core iQ will send the typo-free template out once your campaign is ready to be sent.
Please be sure to mark your template(s) as Active again before your campaign window closes. Inactive templates will fail to Process in the platform and will cause unwanted circumstances. This is especially true for templates that are tied together as Email/Print Alternatives.