Good morning, I have two questions (italian passports)

1. Our daughter is coming to visit for the summer, she has a 60 days tourist visa single entry, she might want to visit neighboring countries can she get a re-entry permit within the validity of the initial stay? If yes can she then still extend the duration of her stay by 30 additional days?

2. Our second daughter will be leaving Thailand to complete her studies back home. She has an extension of stay based on school valid until jan 2025, do we need to cancel it before she leaves or just leave and let it expire (she is 16 years old).

Thanks for your help.