Dear Harry Lime,
Thank you for your attention to our website.
You are enjoying a 30 days Visa exemption on Phu Quoc.
This Visa exemption policy applies only to Phu Quoc Island.
In case you have a new E-Visa, you need to exit Vietnam to Laos, Cambodia,... then enter Ho Chi Minh with that new E-Visa. You cannot enter Ho Chi Minh directly from PQ in this case.
Best Regards,
Heidi Phan