Convert pdf file to pdf/a-3a Format

i use vb6.0
i need to convert pdf file to pdf/a-3a Format
Is this available or is there a special tool for this

@Afisoft

You can use Aspose.PDF for .NET via COM in your VB 6.0 project and use the API to achieve your requirements i.e. PDF to PDF/A-3A. Please check below articles: