competent person apparently in charge of the landlord’s regular place of business or the place where the rent is payable;
704.21(2)(c)(c) By mailing a copy by registered or certified mail to the landlord at the landlord’s last-known address or to the person who has been receiving rent or managing the property as the landlord’s agent at that person’s last-known address;
704.21(2)(d)(d) By serving the landlord as prescribed in s. 801.11 for the service of a summons.
704.21(3)(3) Corporation or partnership. If notice is to be given to a corporation notice may be given by any method provided in sub. (1) or (2) except that notice under sub. (1) (a) or (2) (a) may be given only to an officer, director, registered agent or managing agent, or left with an employee in the office of such officer or agent during regular business hours. If notice is to be given to a partnership, notice may be given by any method in sub. (1) or (2) except that notice under sub. (1) (a) or (2) (a) may be given only to a general partner or managing agent of the partnership, or left with an employee in the office of such partner or agent during regular business hours, or left at the usual place of abode of a general partner in the presence of some competent member of the general partner’s family at least 14 years of age, who is informed of the contents of the notice.
704.21(4)(4) Notice to one of several parties. If there are 2 or more landlords or 2 or more cotenants of the same premises, notice given to one is deemed to be given to the others also.
704.21(5)(5) Effect of actual receipt of notice. If notice is not properly given by one of the methods specified in this section, but is actually received by the other party, the notice is deemed to be properly given; but the burden is upon the party