talk to the hobos in the slums and one will tell you about a junk merchant that sells counterfeit passes. Use those for a low chance to get into Upper New Ark.
If you want a more expensive but fail proof way, go to the massage place and get a few happy endings from Lyn Lyn. Iirc eventually she’ll tell you about a guy that can turn those counterfeit passes into high quality ones for 500 bucks.
Once you have one you can also use an Ink Pen to repair passes yourself but there’s a good chance to ruin them completely. Iirc the INT stat increases the success chance.