Lisa
If you are referring to the code that is used for payments of your ESA (EESA), then it does not mean anything, the code has to be four characters and when the system was set up they typed in "EESA".
Nearly all ESA awards are reassessed on a regular basis, the maximum period is three years.
This is a full review of your claim so you need to complete the form in detail and provide evidence as you can, even if it has been previously sent.
Whilst there have been no changes to the criteria against which you are being assessed, the DWP have amended their guidance in several areas, so make sure that use our current ESA Claim guides to help you with the form.
www.benefitsandwork.co.uk/help-for-claimants/esa1 Gordon