How to replace a relay?

[AquaO]

I noted recently by plugging the light of my quarantine on relay # 7 it ​​did not work.
I have no idea when it stopped working because I did not use it often.

I want to know how to replace this relay??
I checked the box to open it and it looks sealed??

thank you Eric

[rimai]

It is lightly welded.
You can prop it open with a little bit of force.
If you don't want to do that and prefer to send it in for repair, please send me a PM.