The Board of Immigration Appeals has concluded that when the Department of Homeland Security states that an applicant may be removed to a specific country, the applicant may seek withholding of removal from that country in withholding-only proceedings, even if that country is different from the country that was originally designated in the reinstated removal order on which the withholding-only proceedings are based.
In this case, the applicant indicated that he was actually a citizen of Honduras, despite having been previously removed to Mexico, and the Department of Homeland Security indicated it would remove the applicant to Honduras.
The full text of Matter of A-S-M- can be found here:
justice.gov/eoir/page/file/1385691/download