Learn English – What do I call someone I hire to do the personal work for me

I don't know of any specific terms for the person or the cancelled leave, but I wonder whether your colleague might have said "bump", not "pump".

I could understand someone referring to the leave being bumped, i.e. moved to a new position (date). (See definitions in The Free Dictionary).

The alternative day off may also be referred to (at least in the UK) as a "day off in lieu", i.e. as a day off instead of the public holiday. (See definition in Oxford Dictionary Online.) In fact, in the UK you will sometimes be entitled to two alternative days off if you were required to work on a public holiday.

A delegator. Please find the definition and edit my answer.