You tell the Pi to accept a DHCP address by removing the static or inform section of /etc/dhcpcd.conf. Also remove any attempts to define a static IP in /boot/config.txt and /etc/network/interfaces.
To define a static IP and a list of domain name servers in /etc/dhcpcd.conf:
Code: Select all
static domain_name_servers=192.168.1.1 188.8.131.52
The netmask (/24) has to match the way your router is set up. 23 for you?
ps I think routers maintain a table of MAC addresses and the IP allocated. Perhaps rebooting will clear this, or else the router's admin pages should let you clear the stored value for the Pi