Hi! I'm having issues keeping my Swiss Meringue Buttercream pipe-able. Once the buttercream is taken out of the fridge to soften a bit in order to pipe flowers, it turns to soup (albeit a delicious soup, but soup all the same). Is it supposed to be whipped again to make it workable? 

Thank you! 

Get a very small portion (1/4c), microwave it for 10-15 secs then add it to your BC and whip. It'll come together again.

Yes, you have to re-whip it. I guess your meringue wasn't stiff enough when you added the butter in the first place. Add some blobs of butter  or shortening towards  the end if it doesn't come together properly and keep  whipping. 

I'll make another batch and whip the meringue longer. Thanks again!