ðə pɹˈɑːbləm hˈɪɹ ɪz ðˈæt, ɔːlðˈoʊ ᵻlˈɛktɹɑːnz ænd ˈɛnɚdʒi ɑːɹ ɛkstʃˈeɪndʒd wɪð ɐ ɹˈɛzɚvwˌɑːɹ, ðə mətˈɪɹiəl hˈoʊst ɪz nˌɑːt ɐlˈaʊd tə tʃˈeɪndʒ.
The problem here is that, although electrons and energy are exchanged with a reservoir, the material host is not allowed to change.