A drawing frame is not a element in its own right, but a collection of normal drawing elements. All these elements are simply added to the current file when you insert a drawing frame. If a drawing frame is already loaded, the elements of this frame must be removed before you insert the new drawing frame. This can be done automatically if the margin settings of the current drawing and the file type of the drawing frame are correct. Drawing sheet variables and Unit/Field designation will remain, if the new drawing frame also contains these elements.
Hint's
The margin settings are a basic requirement to remove the elements of the existing drawing frame. As the drawing frame is not a element of its own all elements are considered as part of the drawing frame which are located within the margins. If elements of the old frame are not removed please check the margin settings!
To copy the margin setting into files without margin settings, use an ‘empty’ drawing frame (no graphic element at all) with correct margins. No replacement will happen, only the settings will be copied to the files.