To change Username of your Login account please follow this steps
Step 1: Login to our application
Step 2: Navigate to Setting--> Team
Step 3: Enable Editing tool button from right top corner, to change your Email ID as shown below:
Step 4: Select email ID to change with your new Email and save it as shown below:
Once the Email has been updated, an Email notification will be sent to the updated email ID.
You can click on the link for a video tutorial: