To get a meter changed, you need to contact the existing supplier.
ESB networks - who do all meter changes, will only take a meter change instruction, from the current supplier. They do not take instructions for meter changes, from the end customer.
You should contact the existing supplier, to discuss the options available, get more information, look at suitable tarriffs etc, and decide, if a meter change is required.
If a meter change is the decision, you then get the current supplier to put through the meter change request, to ESB networks.
Once that is done, contact ESB networks to check they have
1)received the meter change, (if not go back to the supplier and request again), once it has gone through, then,
2) get an update from ESB Networks, on progress, and date and time of install etc.
Some tarrifs cannot be implemented, as they are meter type dependant, such as a Day/Night tarriff, which is dependant on the meter being a day/night meter.