AFC Bournemouth will head to the Alexander Stadium to face the Baggies, aiming to book a spot in the final against Plymouth Argyle.
Argyle defeated Burnley 4-1 on Sunday to progress to the final two, as the Cherries trip to the midlands was postponed due to conditions at West Brom.
Sunday’s hosts are in the National League Northern Premier Division, while Bournemouth are in the equivalent southern league.
They sit in midtable, with 15 points from 12 games leaving them sixth.
Helen Bleazard’s side have only lost once in all competitions this season, to WSL leaders Manchester City in the FA Cup, and they’ll look to continue that run and reach the final of the National League Cup.
Bournemouth were due to face AFC Wimbledon in the league at the Ringwood Community Hub this weekend, but that game has been moved to accommodate this rearranged fixture.
A date for that fixture will be announced in due course.