The same conjugation applies here as for the する verb on its own.
General conditional (Provisional) 脱すれば
Past conditional 脱したら
Potential 脱できる
And so on...
*also as a side note ～ければ is used for provisional form with 形容詞
Hope this helps.
Ah... This is an unusual verb in that it doesn't follow any of the "common" conjugation patterns you're likely to learn. JJS is correct about 脱すれば and 脱したら, but the potential form is actually 脱せられる (だっせられる).
If you want to know why, I can't explain it all here, but in old Japanese, verbs were conjugated differently. You rarely see any of that conjugation in modern-day Japanese except for very specific verbs like this and things like ～ず (e.g. 食べず、脱せず). It might be hard to understand if you haven't studied old Japanese, but this is the page I referenced: http://wikimatome.org/wiki/%E8%84%B1%E3%81%99%E3%82%8B%EF%BC%88%E6%B4%BB%E7%94%A8%E8%A1%A8%EF%BC%89
Scratch that. I thought about this some more and consulted with a Japanese friend of mine, and the most common/normal way to do potential form for that verb is just 脱することができる. 脱せられる would be some weird passive form like getting permission from someone else to 脱する.
Thank you guys, very clear. 脱することができる was actually what I had written initially in a sentence, and then my mind went: "Wait, shouldn't every verb have a potential form?" But apparently not. I wonder why I never knew about this, it's not exactly an obscure word.
How do I conjugate this?
I mean past is 脱した obviously. But what is conditional? Like with -kereba. だっしければ? Or 可能形... だっできる? Probably a dumb question but I'm clueless.