Times Jumbo 1121

[stevenj]

This is me again asking for help in improving my skills (they're not too bad thanks to all the guidance I have been given!)
Three clues where I think I know the answer but cannot work out the "play" part of the clue

"One company abandoning French area is protected" I think the answer is 'immune' (protected) but what's the rest of the reasoning please?
"Fail to catch? Take out of slips." Miss? I have ?i?s

"What makes mom more subject to change?" I have ?e?o?m so the answer seems to be reform (though it could be deform I suppose) but why?

As always I'd be grateful for guidance. Thank you
Steven

[Lie-in King]

10d Immune - 'I' (one) + '(Co)mmune'

21a Mis(take)s

45d Re for m - makes 'mom' 'more'

[stevenj]

Dear Lie-in-King
You are brilliant! And so kind to help me yet again. You have been my main 'tutor' helping me to become quite good. And you have been so generous in your guidance and support. Thank you.
And just in time before She Who Must Be Obeyed orders me to the bath and then bed
Thank you again
Steven

[Lie-in King]

Hi Steven! I'm happy to help if I can & it's always a pleasure - be well :-)

[stevenj]

Thank you Sir ( I assume you are a Sir as you are a King!). As I said you have been a real inspiration to me. Although it was a teacher who set me off on the crossword route, you and a few others are the ones that really helped me understand how they work. But sometimes ( and it's often little words that defeat me) I still need help. But I hope to crack them too one day. Part of the trouble is that She Who Must Be Obeyed will only allow me to do the weekend one so that it doesn't interfere with homework. Still it's good to be able to do the Big One!
Thank you again Sir
steven