Updates a customer contact or site contact.

• firstName is required
• NOTE: To update the main contact of a CUSTOMER, please use the /customers endpoint.
  • When the contact to update is of type CUSTOMER:
    • isMain cannot be set to true and is optional. To update the main contact, use the '/customers' endpoint.
    • isBilling is optional and defaults to false.
• NOTE: To unset the main contact of a SITE as non-main is not allowed, either use the create endpoint or update another contact of this site and set it as the main contact.
  • When the contact to update is of type SITE:
    • isMain is optional and defaults to false.
    • isBilling is optional and defaults to false.
    • If the contact to update is the main and billing contact of the SITE, the isBilling flag will have no impact and the contact details will be updated. If you want to change the contact that is assigned as the billing contact, please use the create method or update another contact of this site and set it as a billing contact.
• contactItems is required and must contain at least one item.
  • It will replace the existing contact items.
  • To update a specific contact item, you have to provide the id of the contact item to update. Otherwise, new contact items will be added.