In Teamleader you can link one quotation to one deal.
Does your client ask for another offer regarding a different service/product? The best thing to do then is to create a new deal. This way you are able to follow up on your offer meticulously.
Does the client ask to edit the existing quotation? Then you can edit the quotation by going to the section 'Follow up on your open deal'. Click on the 3 dots next to your quotation and select Edit.
Teamleader saves all the older versions of a quotation but in the overview, always the most recent one is shown. You can find and check the older versions of your quotation by clicking on your quotation to open the pdf preview. Click on Show history at the top of the page:
You can also find this history by navigating to the Files on the customer's page. Right-clicking the quotation then gives you the option to show the history of it. More information can be found in this article.