if you can get the consent, it will be better, but you can still allege abandonment if it cannot be acquired.
here is the rule on Domestic Adoption so you can have an idea:http://elibrary.judiciary.gov.ph/index6.php?doctype=Amendments%20to%20the%20Rules%20Of%20Court&docid=a45475a11ec72b843d74959b60fd7bd64564763672711
the process really begins with putting together the docu requirements:
1. Authenticated birth certificate
2. Marriage Contract or Divorce, Annulment, Declaration of Nullity, or Legal Separation documents;
3. Written consent to the adoption by the legitimate and adopted sons/daughters, and illegitimate sons/daughters if living with the applicant, who are at least ten (10) years old;
4. Physical and medical evaluation by a duly licensed physician and psychological evaluation by a psychologist;
5. NBI/Police Clearance
6. Latest income tax return or any other documents showing financial capability, e.g. Certificate of Employment, Bank Certificate or Statement of Assets and Liabilities;
7. Three (3) character references, namely from the local church/minister, the employer, and a non-relative member of the immediate community who have known the applicant(s) for at least three (3) years;
8. 3x5 sized pictures of the applicant(s) and his/her immediate family taken within the last three (3) months;
9. Certificate of attendance to pre-adoption fora or seminars.