I have lots or miles on my M&M account where i still have SEN status for half a year, however i moved to TK M&S and credit all my travels there (already reached Elite).

now i'd like to use some of M&M miles to run upgrades, but at the same time i'd like to keep earning on M&S, is that possible?

example...next friday i fly LOT to Canada and i have a paid ticket in Economy. can i get miles on TK and upgrade by using LH?
how to make it work?
don't want to risk a wrong credit as i need the miles to reach Elite+

rgds