USPTO did a good thing over the weekend. USPTO added a feature to Private PAIR that lets you change the entity size for a patent application yourself.
To change entity size, you 
start by finding your patent application in Private PAIR. In the “Application Data” tab, PAIR will tell you the current entity status. In the case shown in the figure, the size is “undiscounted” which means “large”. Then click on “update”, and a new window will open. At that point you can check a box to change the entity status. 
Fill in a few more blanks, and the entity size will be updated automatically.
In our office, the way this will help us the most is when we are getting ready to pay a maintenance fee and we see that the entity size is wrong. Traditionally the only way to get the entity size updated was to send a fax to RAM and wait and wait for someone in RAM to read the fax and to act upon it. But now it is just a matter of a few mouse clicks to update the entity size, and then you can pay the maintenance fee for the correct entity size.
This is very handy for switching to small entity or back to undiscounted. However, it seems that you still would need to file a certification of micro entity status in addition to the change in PAIR. This is my guess, although I saw nothing dealing with this issue in any of the press releases.