reporting a change in circumstances .

hi all , my wife has been working part time 5 hours weekly but due to her medical conditions worsening she has now had to give notice that she will no longer be able to work, how do we notify the dwp as they were aware of her employment and they deducted all money earned over £20 from our esa payments can i send them a letter recorded delivery to inform them about the change without the need to telephone them, many thanks reds123.

thanks pete, she does not have a work coach as she is part of my esa claim and she is my appointee due to my medical conditions so i think she will just notify them by post. many thanks .