Rule 1033. Amendment
(a) A party, either by filed consent of the adverse party or by leave of court,
may at any time change the form of action, add a person as a party, correct the name of
a party, or otherwise amend the pleading. The amended pleading may aver
transactions or occurrences which have happened before or after the filing of the
original pleading, even though they give rise to a new cause of action or defense. An
amendment may be made to conform the pleading to the evidence offered or admitted.
(b) An amendment correcting the name of a party against whom a claim
has been asserted in the original pleading relates back to the date of the
commencement of the action if, within ninety days after the period provided by
law for commencing the action, the party received notice of the institution of the
action such that it will not be prejudiced in maintaining a defense on the merits
and the party knew or should have known that the action would have been
brought against the party but for a mistake concerning the identity of the proper
party.
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