changing password costs you nothing, I assume password to your waves account on waves lite client
simply just re-import your wallet using current seed and set new password
password here is not for securing your account on the server but
for encryption purposes, waves lite client is a client-sided interface... cmiiw

@MaGNeT
is the alias locked to a single address permanently?
can we change the pairing (alias~wavesaddress) at later time?