Welcome to the forum.
All the flush mount interior ceiling lights have spring loaded bails retaining them to the headliner cutout.
Just use your fingers and pull the lamp away from the headliner.
The lamp in this link is similar, using the same spring retention.
https://www.fpmarine.com/Barnegat-light-QL-CL-TM-C-p/ql-cl-tm-c.htm
If by replace it, that means the burnt out bulb, I have retained usage of the halogen bulbs. I find that the 10W 12V G4 base clear bulbs works best for me. I purchase a 10 pack and replenish when it gets low.