After uploading, you can always update your book (including the files, metadata, and the prices) and save the changes. There is no need to withdraw the book or upload an 'updated' version.
To make changes after sending your book to stores, go to your My Books page and click on View Book or More > View & edit under the book's title. Once you are on your book page, you will need to select 'Click to edit' to unlock the page and be able to make changes.
You'll be able to change anything (price, title, description, etc.), or even upload an updated version of your book. (To upload a new file, simply drag & drop it in the file field.) You can always download your already uploaded files with the little download arrow in the top right corner.
You can change everything without withdrawing the book, even upload a new file. (If you are running into errors, please check this article.) The only detail you cannot change after publication is the ISBN, we are unable to add this later on. It is also not recommended to completely change the title or author name of a published book because it causes negative user experience for buyers. Your changes will be sent to stores once you press "Update" and take place within a few hours or days.