Try to use following method:
1. Remove old NS record from all domain's DNS zones:
# for i in `mysql -uadmin -p\`cat /etc/psa/.psa.shadow\` psa -Ns -e "select name from domains"`; do /usr/local/psa/bin/dns --del $i -ns '' -nameserver ns2.test.tld; done
2. Add new NS record for all domains:
# for i in `mysql -uadmin -p\`cat /etc/psa/.psa.shadow\` psa -Ns -e "select name from domains"`; do /usr/local/psa/bin/dns --add $i -ns '' -nameserver ns.test.tld; done
3. Update and reload new zones:
# # for i in `mysql -uadmin -p\`cat /etc/psa/.psa.shadow\` psa -Ns -e "select name from domains"`; do /usr/local/psa/admin/sbin/dnsmng -update $i; done
Note, it is just example. Modify it as you need.