An altar (n.) is an elevated place (like a type of table) where religious ceremonies are performed, or where offerings are left for the gods or spirits:
The verb alter is a more formal word for change.
- Art has the potential to alter our perception of the world.
- These vegetables have been genetically altered to be richer in vitamins.
- You can re-publish the article in its original form; it may not be altered.
The noun form is alteration:
- I made a few alterations to the project proposal.
= I made a few changes to the project proposal.
- May I suggest one alteration to the schedule for the conference?
= May I suggest one change to the schedule for the conference?
Again, this word is a little more formal. In casual spoken English, we can simply use the word “change” as both a noun and a verb.