When you want to change the static elements from your production file, or simply change the size of it, you can replace the base file.
By clicking on replace base file, we can change the base of the production file without interfering with the personalizable elements already placed in the template.
To replace the base file
Click Replace base button 
Read carefully the warning. We recommend changing the base file with one of similar size. If the file of the newly uploaded base is much smaller than the existing one, some personalizable elements can be left outside of the canvas. 
Browse and choose the new file you'd like to use as the base
Note:
If you were using an EPS as a base you will be able to replace the base file only for another EPS. If you were using an image as a base file, you will be able to replace the base file only for another image.
