karyn1,
I always repot mine when they need it-blooming or not. I haven't noticed any bloom drop from this. I repotted 6 blooming passies this year. 5 are blooming (the last one I repotted in too large of pot and is getting larger but not blooming again yet.)
When you repot, do not pot up over about 2 pot sizes though, because they seem to bloom much better potbound. If they have alot of new root room all of a sudden, they will put energy into growing roots and foilage and not blooms right away.
I would rather have to repot more often and have more blooms so I usually only pot up one pot size at a time. If it is a really hot day I would do it in the shade or in the evening, and water immediately after repotting and leave it in dappled shade a day or two to recover. Make sure to use well drained soil with lots of perlite added. Good luck
~SJN

I transplanted them and the blooms were unaffected. I did go into a much larger pot on a couple but those had not begun to form buds. Thanks.
Karyn