Answer:
cant give you a sample coz that would make ur speech sound fake. you should mention the persons qualities, what people like about them, how good a friend they are and how much they'll be missed. also try adding some humour by mentioning somethign funny they did, but only if they wouldn't be embarrassed or angry about it.
If the person has not qualities, wont be missed and isn't that great a friend, say maybe a boss who thinks the world revolves around them, just make it up. say the thinks you think they would like to hear. and if you're never going to see them again, tell all the embarrassing stories you like, what are they going to do about it?