fix it
Its called fixing something that is broken.
mend
repair means when you fix something
A material covering a hole is called a patch. It can be used to repair damage or prevent something from escaping.
Repair is fixing something that has broken, alteration is improving something.
To mend it
Alteration is a change made to something. Repair is an attempt to make something work exactly as it did before. Repair you fix the thing alteration you change it.
it can repair itself
fix
You fix it or mend it
To fix it.
to fix or to mend