Standing and Eating and making Mezumin

3 people eat together a meal and have no place to sit…and consequently
stand up for the whole meal (I am not dealing with Derech Eretz in this question)
Can they make a mezumin…or does Kevias Seudah actually mean sitting to eat.
And if you were not able to sit, then it is not considered Kevias Seudah.

Abie

Sitting is a requirement.