How to iterate over already created items?

Terraform
1

Hello,
what is the proper way to create an additional resource?

E,g.

Step 1

variable user_names {
 type = list(string)
 default = ["user1","user2"]

resource "aws_iam_user" "example" {
  count = length(var.user_names)
  name  = var.user_names[count.index]
}

Step 2:

variable user_names {
 type = list(string)
 default = ["user1","user2",**"user3"**]

It is my understanding that the code above will fail because user1 and user2 already exist.

What is the proper way of handling such a situation?

Thank you
AZ

2

it is a magic.

// Resolved.