N.Y. SCP Law § 401

§ 401. Appearance of parties\n 1. Who may appear. A party other than an infant, incompetent or\nconservatee may appear and prosecute or defend a special proceeding in\nperson or by attorney, except that a corporation or voluntary\nassociation shall appear by attorney. An infant by the guardian of his\nproperty, an incompetent by the committee of his property and a\nconservatee by his conservator may appear and prosecute or defend a\nspecial proceeding in person or by attorney as provided in 402.\n 2. How made. An appearance is made by pleading, by waiver, by serving\nupon the attorney for the petitioner and filing with the clerk a signed\nnotice of appearance or by appearance in person noted upon the record in\nopen court. The notice may be signed by any person authorized under\nsubdivision 1 to appear for the party.\n 3. Evidence of attorney's authority. Where a party is a\nnon-domiciliary or has not been served personally with process within\nthe state the court may require\n (a) that any person appearing for the party furnish acknowledged\nevidence of authority so to appear and\n (b) the authorization to set forth whether there has been executed\npreviously by the party\n (i) any power of attorney or similar instrument relating to the\nparty's interest in the estate and\n (ii) any assignment of the interest.\n 4. Appearance by waiver of process. Any adult competent party may also\nappear by an acknowledged waiver of issuance and service of process\nwhich upon filing with the clerk is equivalent to the filing of an\nacknowledged notice of appearance under subdivision 2. In a probate\nproceeding the waiver shall state the date of the will to which it\nrelates and that a copy has been furnished or examined.\n 5. Termination of appearance of consul. When a consular official shall\nhave appeared in behalf of a noncitizen, a subsequent appearance by the\nattorney in fact of the noncitizen pursuant to recorded power of\nattorney or appearance by an authorized attorney shall terminate the\nappearance of the consul.\n