How to change the column name after timechart output

[ravir_jbp]

I am created below query to get the hourly report of certain tasks. I go the final timechart values for four different "connectiontype" below. But I like to rename the column name to something else.

[ITWhisperer]

| rename 'old field name' as "new field name"

or, change the field values before the timechart

| eval connectionType=case(connectionType=="old field value 1","new field value 1", connectionType=="old field value 2", "new field value 2", true(), connectionType)