Regular License - Editing, Processing the website after transferring the endproduct to client


I am a little confused over the further work on the website after transferring the end-product to the client with the regular license.

Am I allowed to edit the website over a third-party provider after transferring the end-product (and thus the license as well) to my client or am I obliged to conclude a new contract with my client with the purpose of service and editing of the website on behalf of him?

Even if one of those options are possible, is there another possibility to keep the website one my one and then keep editing the website for a client without transferring a ‘end-product’ and the license to my client? Like just in the meaning of, it is my website but the content is referred to someone else and therefore no end-product is existent?

Thanks in advance.