This workplace goodbye letter is written from the entire staff to a departing coworker.
Dear {Recipient},
We're all writing as one voice here to send you off with one big farewell. That's better than a bunch of individual goodbyes, right? Maybe it would help if you imagine the whole group of us yelling this at you in unison.
It's a shame you won't be around to be a part of {something fun the office does, a big project coming up, etc.}. We were all looking forward to it, and now you'll just have to hear about it secondhand. Oh well. We know you're going on to do bigger and better things at {new place where coworker is going}, so we'll try to be happy for you, instead of insanely jealous.
We hope you'll keep in touch. You know you'll at least be hearing from {someone in the office} when {something big happens to that person, like the birth of a baby, promotion, etc.}, so be looking out for that. Until then, have a blast at {new place}.
Knock 'em dead,
{Senders}