Change expired user password on sql server from linux
There may be a better solution to this, but I often faced similar issues with Mac users whose passwords would expire, and due to lack of SSMS were unable to reset themselves.

I took to having a SQL Agent job to email any known non-Windows users of their password expiration 7 days out so they had plenty of time to issue the password reset themselves. This annoyingly requires keeping track of these users, but in a Microsoft shop it was manageable as it was only a few people.

In this case, if the account is already locked, ask your DBA to reset it and inquire about some sort of warning system like the above in the future. Or, like you said, find a willing Windows user to help you out.