Getting Baby To Move For Scans

Has anyone got any tips on how to get baby to move into the right position for scans? At my 12 week, they were lying face up, so had to be rebooked, and for my 20 week today, they were upside down, and wouldn’t move at all, so having to go back next week! I tried rolling onto each side, going for a wee and jumping up and down, but no luck! Any tips would be appreciated! Thank you! x