You cannot change a username once it has been created, that is a restriction within ASP.NET. But you can create a new user in ASP.NET and link it to the Customer in Commerce.

Something like:

// Create new user

var target= Membership.CreateUser(newUserName, newPassword, userEmailAddress);

if (RoleExists(AppRoles.EveryoneRole) &&!SecurityContext.Current.CheckUserInGlobalRole(target, AppRoles.EveryoneRole))

SecurityContext.Current.AssignUserToGlobalRole(target, AppRoles.EveryoneRole);

// Add user to registered role

if (RoleExists(AppRoles.RegisteredRole) && !SecurityContext.Current.CheckUserInGlobalRole(target, AppRoles.RegisteredRole))

SecurityContext.Current.AssignUserToGlobalRole(target, AppRoles.RegisteredRole);

// Get Customer

var customerContact = CustomerContext.Current.GetContactForUser(currentUser);

//assign new user to customer

customerContact.UserId = ToTypedString(target.ProviderUserKey);

//  save customer

customerContact.SaveChanges();

// delete 'old' account

Membership.DeleteUser(oldUsername);

Hi, 

Seems like it was discussed earlier here :

http://world.episerver.com/Forum/Developer-forum/-EPiServer-75-CMS/Thread-Container/2014/7/Change-Username/

Hi sapna,

I haven't worked with Commerce before, I tested this with EPiServer CMS 7.5 only.

I guess you only want to change the username, and keep the old email.

Usernames are stored in the Users table. UserName is not PK / FK / unique constraint, so you can safely change it there.

User access rights are stored in tblContentAccess table. You need to change the Name column (free text).

Just make sure that 'new username' is not already in use.