1. Created a new annotation fc. Spatial reference of the new annotation fc was imported from the original annotation feature class to have same spatial reference. 2. Append annotation (First input must be the new annotation fc, and second is the original annotation fc)3. Load the new appended annotation fc into the ArcMap. All the annotation texts will become very large. But envelopes are fine.4. Select many annotation features using annotation class and edit them, change it's properties to have smaller font size.