A Thursday date - necessary due to the fact Blackburn face Manchester City the previous Monday in the Premier League - has now been agreed upon with the game kicking off at 8pm. It is due to be televised live on Sky Sports.
As a result, Blackburn's league game at home to Fulham - due to take place on Saturday January 16 - has been put back 24 hours.
The second leg keeps its slot on Wednesday January 20, the Villa Park clash kicking off at 7:45pm.
Tickets already issued will be valid for the new dates.
The other semi-final tie between Manchester City and Manchester United was also postponed this week.
New dates for that tie had already been announced with the first leg a Eastlands to take place on Tuesday January 19 and the second at Old Trafford on Wednesday January 27.
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