To the query "how does an American citizen in Singapore get something notarized in Singapore"
"Notarisation involves certifying a document as either an authentic copy of an original document, or as having been validly executed. Notarisation is done by a notary public, who is generally a senior lawyer practising in Singapore who has been approved to act as a notary public under the Notaries Public Act."
Looks like you may have to look for an attorney over there |