Log shipping in sql server
Assuming you have taken log backups since the log file grew, you should be able to shrink the file without changing recovery models.

But you absolutely, 100% have to understand that shrinking the log file is an absolutely useless activity if the log file is going to grow again. Let it stay as big as it's going to get during normal operations, because shrinking it to free space temporarily doesn't gain you anything. What will you use that space for today when you know that tomorrow the log file will grow again? This is like watering the lawn right before a thunderstorm. Perhaps you are not backing up the log often enough? Doing it more often 

Please read this in full before proceeding. And I really mean in full. Like, the whole thing.

Now, if you have read that entire page, and are absolutely, 100% sure that you need to shrink the log file, and that it is a worthwhile activity because you know the log file won't grow again, then:

USE your_database;
GO
DBCC SHRINKFILE(your_database_log, 100); -- hypothetical, target size is in MB
GO


If you don't know that the log file won't grow again, put the mouse down and leave the log file alone.