Rename two columns of a Tabular object:

Alternatively, use indices to specify which columns to rename:

Rename the first two columns of a Tabular object:

Take a Tabular object:

Rename some of its columns by using rules oldkeynewkey:

Alternatively, use indices on the left-hand side of the rules:

Use a mixture of notations:

Take a Tabular object without column keys:

Add respective column keys, using "ColumnN" for the column if not specified:

Use RenameColumns[tab,None] to remove all column keys from a Tabular object:

Renaming rules that do not correspond to any existing column are ignored:

With repeated renamings of the same column key, only the last one is used:

New names and old names can overlap, effectively implementing a permutation of column names:

A permutation of the columns themselves can be implemented with Part:

Tabular[tab,newcols] is equivalent to using RenameColumns to rename all column keys:

Take a Tabular object:

Each rule is interpreted here as a column renaming, not as a new column name:

Use another rule to have rules as column keys:

However, using rules in keys requires a more complicated Slot construction, so it is not recommended: