You should ask the business to complete a new test transaction to make sure we pick up their Merchant ID which may have changed. You can do this using one of your test cards or using the card details in the onboarding form here.
The business does not need to complete a new sign up form. Once done please make sure to inform us at merchantonboarding@mi-cnx.com of the business name, card number used and the date of reswipe. We will then get the business relinked to you program.