I ran into a similar situation with a Steam Beer. I made the starter on a Wednesday with plans on brewing the following Saturday. I had to delay those plans until the following week. So I put the starter in the fridge and stepped it up a few days before my brew day by decanting most (but not all) of the liquid from the starter, boiling some more water and DME, cooling that mix to room temp and then pouring it into the starter bottle which I decanted from. That worked fine. I saw some activity in the starter and when I pitched I had a normal fermentation cycle.
On Deck: This will be the summer of wheat beer experiments!
Primary: Pomegranate Wheat, Apricot Wheat, Wine Beer
Secondary: 2012 Washington State Merlot, 2012 Italian Carmenere, 2012 Italian Montepulciano, 2012 Italian Barolo, 2012 Central Valley Viognier
Aging in bottle: 2010 Washington State Merlot, 2010 California Cabernet Sauvignon, 2011 Washington State Cabernet Sauvignon