The portal could be tweaked by using the customization features available with Freshdesk - the level of customization depends upon the plan you are on. Sometimes, you would want to revamp your portal for which you need to start from scratch and you would want to reset the existing changes made to the portal. 

Please navigate to Admin --> Channels --> Portals --> Customize Portal to be taken to the page where you can make the customization changes. Once you are there, browse through any or all of the tabs there, to go to the bottom of the page and find the Reset button - when you click on this, you would be given two options - reset to last published or reset all changes. Please choose the option based on your requirement.