Generally amendments of any process, proceeding, pleading, or record are allowed at any time in furtherance of justice, upon such terms as may be just. A plaintiff can file a motion to amend the complaint and a defendant can file a response to the same. The court after hearing the motion can allow or disallow the amendment. If allowed, the court gives an order granting leave to amend the complaint. In some cases when the original complaint has some material deficiencies the court can permit the plaintiff to file an amended complaint within a prescribed time period.
Leave to amend a pleading shall be freely given when justice so requires. This is generally interpreted to allow a plaintiff to at least amend his complaint one time in an attempt to state a cause of action unless, of course, it is clear that a plaintiff will not be able to state a cause of action. Ambiguities should be resolved in favor of allowing amendments unless and until it appears that the privilege to amend will be abused. [In re Forfeiture of One 1973 Mercedes Benz Motor Vehicle, 423 So. 2d 535, 537 (Fla. Dist. Ct. App. 4th Dist. 1982)]
The following are the rules in Florida with regard to amendments
Fla. R. Civ. P. 1.190. Amended and Supplemental Pleadings
(a) Amendments. --A party may amend a pleading once as a matter of course at any time before responsive pleading is served or, if the pleading is one to which no responsive pleading is permitted and the action has not been placed on the trial calendar, may so amend it at any time within twenty days after it is served. Otherwise a party may amend a pleading only by leave of court or by written consent of the adverse party. If a party files a motion to amend a pleading, the party shall attach the proposed amended pleading to the motion. Leave of court shall be given freely when justice so requires. A party shall plead in response to an amended pleading within 10 days after service of the amended pleading unless the court otherwise orders.
(b) Amendments to Conform with the Evidence. --When issues not raised by the pleading are tried by express or implied consent of the parties, they shall be treated in all respects as if they had been raised in the pleadings. Such amendment of the pleadings as may be necessary to cause them to conform to the evidence and to raise these issues may be made upon motion of any party at any time, even after judgment, but failure so to amend shall not affect the result of the trial of these issues. If the evidence is objected to at the trial on the ground that it is not within the issues made by the pleadings, the court may allow the pleadings to be amended to conform with the evidence and shall do so freely when the merits of the cause are more effectually presented thereby and the objecting party fails to satisfy the court that the admission of such evidence will prejudice the objecting party in maintaining an action or defense upon the merits.
(c) Relation Back of Amendments. --When the claim or defense asserted in the amended pleading arose out of the conduct, transaction, or occurrence set forth or attempted to be set forth in the original pleading, the amendment shall relate back to the date of the original pleading.
(d) Supplemental Pleadings. --Upon motion of a party the court may permit that party, upon reasonable notice and upon such terms as are just, to serve a supplemental pleading setting forth transactions or occurrences or events which have happened since the date of the pleading sought to be supplemented. If the court deems it advisable that the adverse party plead thereto, it shall so order, specifying the time therefor.
(e) Amendments Generally. --At any time in furtherance of justice, upon such terms as may be just, the court may permit any process, proceeding, pleading, or record to be amended or material supplemental matter to be set forth in an amended or supplemental pleading. At every stage of the action the court must disregard any error or defect in the proceedings which does not affect the substantial rights of the parties.
(f) Claims for Punitive Damages. --A motion for leave to amend a pleading to assert a claim for punitive damages shall make a reasonable showing, by evidence in the record or evidence to be proffered by the claimant, that provides a reasonable basis for recovery of such damages. The motion to amend can be filed separately and before the supporting evidence or proffer, but each shall be served on all parties at least 20 days before the hearing.