Just wanted to bring out the following, since some serious words are tossed here like 'revoking' a naturalization certificate.(especailly when it was not obtained by --fraudulently,with material concealment and so on,as the OP seems to have none of these..as per OP postings so far there are none)
Let us see to the extent the provisions exist really what really happens in which scenarios.
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1)8 C.F.R. PART 342—ADMINISTRATIVE CANCELLATION OF CERTIFICATES, DOCUMENTS, OR RECORDS
Title 8 - Aliens and Nationality .
§ 342.1 Notice.
If it shall appear to a district director that a person has illegally or fraudulently obtained or caused to be created a certificate, document, or record described in section 342 of the Act, a notice shall be served upon the person of intention to cancel the certificate, document, or record. The notice shall contain allegations of the reasons for the proposed action and shall advise the person that he may submit, within 60 days of service of the notice, an answer in writing under oath or affirmation showing cause why the certificate, document, or record should not be canceled, that he may appear in person before a naturalization examiner in support of, or in lieu of his written answer, and that he may have present at that time, without expense to the Government, an attorney or representative qualified under part 292 of this chapter. In such proceedings the person shall be known as the respondent.
<<<Note above that notice shall contain allegations.>>>>.
And
2)Section 340 INA Revocation of Naturalization [8 USC 1451] .
(b) Notice to party - The party to whom was granted the naturalization alleged to have been illegally procured or procured by concealment of a material fact or by willful misrepresentation shall, in any such proceedings under subsection (a) of this section, have sixty days' personal notice, unless waived by such party, in which to make answers to the petition of the United States; and if such naturalized person be absent from the United States or from the judicial district in which such person last had his residence, such notice shall be given either by personal service upon him or by publication in the manner provided for the service of summons by publication or upon absentees by the laws of the States or the place where such suit is brought.
<<<INA mentions same thing above>>>.
AND.
3)(a) Concealment of material evidence; refusal to testify - It shall be the duty of the United States attorneys for the respective districts, upon affidavit showing good cause therefor, to institute proceedings in any district court of the United States in the judicial district in which the naturalized citizen may reside at the time of bringing suit, for the purpose of revoking and setting aside the 'order' admitting such person to citizenship and canceling the certificate of naturalization on the ground that such order and certificate of naturalization were illegally procured or were procured by concealment of a material fact or by willful misrepresentation, and such revocation and setting aside of the order admitting such person to citizenship and such canceling of certificate of naturalization shall be effective as of the original date of the order and certificate, respectively
..........so on
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So is there any slightest indication of the above in the letter?seems to me none(as per OPs postings).
If any one knows there are any other law clauses that can 'simply; can cancel the naturalization,please post.
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Note: I am not a lawyer and I am just a lay man without any legal knowledge.!
Read the above STRICTLY at your own risk.