You can change the list limit for a list at any time. If your new list limit allows fewer list entries or data elements (depending on which type of limit you have) than currently exist on the list, list services does not alter the list to conform to the new list limit you have set. However, any IXLLIST requests that try to increase the number of list entries or data elements on the list will fail until the request can be satisfied without exceeding the new limit.