Wait and do a full repot in June instead of potting up.

How exactly did you plan to transplant?

Why not now Dave? I know it's Winter, but if mine, I think I'd do it now. What would you hope to gain by waiting?

In years past I've handled large office Spaths like this by slicing off a couple of inches of those roots w/ a serrated knife; spread the roots w/ my fingers into a pot of fresh new mix. I'd wait a day & then water it in well.

Why not now? Well, if it were to just be "transplanted" and not given a full repot, that wouldn't help at all.

Those roots need some work. All of the soil needs to be removed and the roots need to be untangled and pruned.

If that were the case, and the correct soil was used (I'd recommend 5:1:1) then I would personally do it now. But it takes a bit of time to gather ingredients, learn to make a good mix and have a full understanding of full repotting (keeping the roots moist during the process is important). I am not saying the op doesn't know how to do this or isn't capable, I'd just like to put it all out there that it's more involved than just putting it in a larger pot with new soil on the bottom and sides.

i agree with you Karen, however, my only disagreement would be to water immediately after repotting. There's no sense of waiting a day especially if the mix is dry or a coarse airy one.

Plants grow in phases, sometimes it will look like it's not doing anything but will be working on root development at that time. Sometimes they are just hanging on waiting for the right time to start growing again. Other times it will start on leaves. Right now most houseplants are in semi dormancy. When you pot up/repot at this time of year you are forcing them out of that rest period they need. When you fiddle with roots, or feed it makes the growth less desirable and the plant is more prone to stretching for light which causes deformed growth and the soil will not dry out as quickly causing newly pruned roots to contract rot. There is less light for them to be had,. Their soil is not as warm as it is at other times of the year also. The new growth also tends to be less healthy. It is best to pot up/repot when the plant is just coming out of dormancy, late spring for most people.

None of my tropical houseplants are dormant.

Including my two peace lillys that are in north facing windows. They put out growth all year long including right now.

theyll stop growing if conditions aren't favorable. If they're getting enough light, they'll grow all year, just a little slower in the winter.

Its not about dormancy with tropicals as they don't go dormant. It's about how much energy they have built up this time of year.

They don't NEED a rest period as they don't go dormant and that also doesn't have anything to do with them stretching for light. That just has to do with unfavorable light conditions. Plants usually grow leggy in the winter. Whether you repot or not won't affect that.

Of course the best time to do work would be on the longest days of the year. I.e. Late June.

I'd also wait if you're going to repot, but would be ok with loosening the roots now & potting up until around Father's Day - repotting then. It's not that your plant is going to die if you repot now, just that it will recover very slowly and its defenses will be low during the recovery, leaving the plant susceptible to insects/diseases. The recovery will also be painfully slow.

On occasion, people have pointedly noted that growers can do whatever they wish because it's THEIR plant. This is 100% true, but it doesn't trump the fact that there are a number of degrees of comparison re the timing of repotting that might cover the gamut from poor time to repot to best time to repot. For PLs, the dead of winter gets a 'poor' rating compared to a June repot, which would be the best time to repot. If it was my plant, I wouldn't do anything until around Father's Day, other than to monitor moisture needs.

If I couldn't restrain myself from repotting now and wanted to get busy restoring the plant's vitality and eye appeal, I'd cut the bottom half of the roots off, prune the entire top back to the crown, put it in a fast draining, well-aerated soil that allows you to water correctly, and monitor water needs carefully. That way, all the new foliage that comes in will be pristine. That will happen MUCH faster if done in June, however.

Al