Question about (re-)hemming:

I'm considering purchasing a pair of pants on theRealReal that happen to have had their hem released by a "professional tailor" (or so they say). Unfortunately, I'm not really into that look, but the pants are a steal at the price and I want to buy them anyway. So, my question is, is it easy enough to undo (re-hem) a released hem, and would it be possible for a good tailor to make the hem of the pants resemble their original, store-bought condition?
Thanks!