Yes, it is the Time To Live value that you should reduce. In normal operation it's typically set to between an hour and 2 days. So a day or two before the move, you should reduce it to somewhere from 10 to 30 minutes, as you see fit.
There are 3 common ways the TTL can be defined
- TTL for the zone as whole, which is then inherited.
- TTL set on each entry individually.
- A TTL is set for the zone as whole, and some entries have a individual TTL setting which overrides the inherited value.
How to change the TTL will depend on which DNS server, or DNS hosting service you use. Here is a quick overview of the TTL value in BIND 9's configuration, which is useful since many services model their user interface somewhat after BINDs configuration.