(1) An offer is open to be accepted within the time stated in the notice, which must not be less than 14 days after the offer has been made.
(2) If no time for acceptance is stated in the notice, an offeree may accept the offer at any time before judgment is given.
(3) An offeree may accept the offer by serving a notice of acceptance, in accordance with Form 46 on the offeror, at any time while the offer is open.