【Rails】エラー対処法：This migration uses change_column, which is not automatically reversible. StandardError: An error has occurred, this and all later migrations canceled:

class ChangeClientsAgeToInteger2 < ActiveRecord::Migration[6.1]
  def change
    change_column :clients, :age, :integer, using: "age::integer"
  end
end

class <クラス名> < ActiveRecord::Migration[6.1]
  def up
    <マイグレーション実行時の処理>
  end

  def down
    <ロールバック実行時の処理>
  end
end

class ChangeClientsAgeToInteger2 < ActiveRecord::Migration[6.1]
  def change
    change_column :clients, :age, :integer, using: "age::integer"
  end
end

class ChangeClientsAgeToInteger2 < ActiveRecord::Migration[6.1]
  def up
    change_column :clients, :age, :integer, using: "age::integer"
  end

  def down
    change_column :clients, :age, :string
  end
end

rails-vue# rails db:rollback
== 20210724085421 ChangeClientsAgeToInteger2: reverting =======================
-- change_column(:clients, :age, :string)
   -> 0.0451s
== 20210724085421 ChangeClientsAgeToInteger2: reverted (0.0452s) ==============

# rails db:migrate
== 20210724085421 ChangeClientsAgeToInteger2: migrating =======================
-- change_column(:clients, :age, :integer, {:using=>"age::integer"})
   -> 0.0404s
== 20210724085421 ChangeClientsAgeToInteger2: migrated (0.0407s) ==============

class ChangeProductsPrice < ActiveRecord::Migration[5.0]
  def up
    change_table :products do |t|
      t.change :price, :string
    end
  end

  def down
    change_table :products do |t|
      t.change :price, :integer
    end
  end
end

class ChangeProductsPrice < ActiveRecord::Migration[5.0]
  def change
    reversible do |dir|
      change_table :products do |t|
        dir.up   { t.change :price, :string }
        dir.down { t.change :price, :integer }
      end
    end
  end
end

class <クラス名> < ActiveRecord::Migration[5.0]
  def change
    reversible do |dir|
        dir.up   { マイグレーション時の処理 }
        dir.down { ロールバック時の処理 }
      end
    end
  end
end

class ExampleMigration < ActiveRecord::Migration[5.0]
  def change
    create_table :distributors do |t|
      t.string :zipcode
    end

    reversible do |dir|
      dir.up do
        # CHECK制約を追加
        execute <<-SQL
          ALTER TABLE distributors
            ADD CONSTRAINT zipchk
              CHECK (char_length(zipcode) = 5) NO INHERIT;
        SQL
      end
      dir.down do
        execute <<-SQL
          ALTER TABLE distributors
            DROP CONSTRAINT zipchk
        SQL
      end
    end

    add_column :users, :home_page_url, :string
    rename_column :users, :email, :email_address
  end
end