Do liberals believe that institutions are unchangeable?

Let's first consider what institutions are.

Looking at various dictionary definitions, institutions can be:

• - organizations founded for a specific purpose
• - customs that have been important features of a group or society for a long time. These might include marriage, banking, markets, government, etc.

but probably the best definition that fits your question is this:

• "Institutions are structures and mechanisms of social order and cooperation governing the behavior of a set of individuals within a given human collectivity."

Liberals favor reform and progress, and the protection of civil liberties.

Some reforms might be wrong, but this is only about definitions, not points of view. So we can simply accept that definition.

In fact, if you look at "western" governments and politics, you might be able to identify liberal tendencies in any philosophy of government, even a Conservative one.

But it is also a fact that reform and progress of a society and its laws and government is only possible if institutions are subjected to review and reform in some degree.

So, unless the maintenance of civil liberties is, by definition, an institution, the answer to your question is "No, Liberals do not believe that institutions are unchangeable."

I've heard people say that the concept of reform and change has become an institution of Liberalism, and therefore Liberals should seek to change it.

That is frivolous and only makes things more unclear.

What is more accurate is to say that Liberals favor review and progress. Some things do not need changing for everybody. But without the desire to investigate and examine, there can be no improvement.

The statement "We don't need to change, because we have always done things this way " is to some an open invitation to look at ways that change might bring about improvement.

But the greatest enemies of our society are:

• the unwillingness to accept change, and
• the insistence on change for the sake of change.