A Singapore lawyer can conduct a name change for a foreigner with a deed poll executed in Singapore. However, the laws and regulations of your home country will determine whether or not they will recognise the name change.
It is advisable to check with the Singapore embassy or consulate office to determine whether or not a name change made in Singapore will be recognised in your country. This can be done to determine whether or not your last name was legally changed in Singapore.
If you want to alter your name in the documents issued to you from that country, you might be required to go through the process of executing a deed poll in your home country.