Fix update agentName

src/Managing.Application/Users/UserService.cs

@@ -168,9 +168,9 @@ public class UserService : IUserService
         if (string.IsNullOrEmpty(agentName))
             throw new Exception("Agent name cannot be empty");
 
-        // Check if agent name is already used
+        // Check if agent name is already used by another user
         var existingUser = await _userRepository.GetUserByAgentNameAsync(agentName);
-        if (existingUser != null)
+        if (existingUser != null && existingUser.Id != user.Id)
         {
             throw new Exception($"Agent name already used by {existingUser.Name}");
         }