How do I change cutting area from Machine presets

I used all parts from Sienci Labs and modeled my CNC router after the Longmill 30 x 30, I need to change the preset to a 48" x 48" cutting area.
Thank you in advance for any help.

Fiddle

Hi

For a Longmill , these settings can be changed using Gsender , under the heading Firmware.

Assuming you have read and have a clear understanding of the following

These are the settings for machine extents

$110, $111 and $112 – [X,Y,Z] Max rate, mm/min