If you would like to change scale of your drawing, open your drawing, then go to Environment>Drawing Page, choose the Scale tab and type in the Scale, eg. 1″=8’. After you have to change the scale, you will need to modify the text, leadered text and the arrow heads of the leader so that they are legible.
Please note: The above settings change will be the default for the current drawing.
Alternatively, you can copy and paste into a new drawing of the scale you would like to use, that way all the settings for the text and text with a leader will be the size set for that scale. Here are some instructions to assist with copying and pasting to a new drawing: Copy and Paste to a New Drawing