Change date format using excel app for iPad (Office 365 Personal)

Hi there, I’m using MS excel on my iPad and I wonder how to change the date format from dd-mm-yy to mm-dd-yy

When I select the cells and date format button there is no chance to change the format , there’s only options but related to my region and I need US format, there is no chance to personalize as it happens on the PC/Mac version

Can somebody give me a hint on this matter? Thanks in advance