Hi Mucci,
I understand those users want to be able to wipe the mail account off their iPhone, however no erase everything on the phone when they leave.
If so, for my experience, it is unavailable at this time. We are not able to wipe the mail account only. However, it is highly appreciated to submit feedback about this requirement.
Many features of current programs were designed and upgraded based on customer feedback. Again, thank you for working closely to improve our products and service.
Thanks,
Luke Yan