Updates and existing account in the Postalytics system.
This account can be a free standing account or it can be a sub-account
of an agency if an agency id is passed in.
A successful return will contain the API key for this account along with
the user id of the new account.
The first name of the account holder.
The last name of the account holder.
The password associated with the account. Must follow password guidelines.
The username associated with the account.
The city associated with the account's address.
The state associated with the account's address.
The street address associated with the account.
The zip code associated with the account's address.
The company name associated with the account.
The email address associated with the account.
The phone number associated with the account.
The unique account identifier.
The date and time when the account was last updated.