#MATL, 15 bytes
`jt]Nq$Xh2Y2bXE
The input needs an extra trailing newline (this is used for marking the end of input).
` % do...while loop
j % read a line of input
t % duplicate. Used as loop condition: if not empty proceed with next iteration
] % end loop
Nq$Xh % concatenate all strings except the first into a cell array
2Y2 % predefined literal: 'abc...z'
b % move first string to top of stack
XE % transliterate. Implicit display