change column data type of a big table

I have a very big table, in fact only this table uses approx. 60% space of
disk.

The table is an standalone table (no one inherit from this and this is not
inherit from another).

I need to change a int column to bigint.

But aparentely this alter recreate the table, my problem is the space, there
are no space enough in disk.

Is possible to change column datatype without recreating the table?

Thanks!