Rerolling gear?

Don't worry. Reroling is very cheap. If you Run GG several times you ll have a decent amount of semi enigmatic scrolls.
But if you stoped playing for a long time you will have to get new gear which you can roll as you want for free. Just check it out

Funny how moderators and admins couldn't be bothered to answer a simple question a whole day (too bad it was in the right section, so no need to post useless comments about moving it) but when you point that out to them they instantly get 'offended', warn and ban you for 'disrespecting' them, as if they deserved my respect in the first place. Anyone sees a pattern? Nah, don't reply - they could get offended again. L-M-A-O Not even funny but better smile for good health.

Quote from Jetboy

Is there a way to change them without much cost, or would it be faster to reroll new character(it takes about 2 days)?

First, welcome back!

Remaking your character would cost you much more than a few semi-enigmatics because you won't get League of Levellers freebies a second time for the same class. Even without the levelling event, it's highly not recommended to relevel just for that as you'll just waste your time for nothing unless you enjoy levelling or want more alts. Or you forgot to use a BuddyUp code.

To get up to speed with how things work now, you can take a look here:
How to Tera (+level 65 beginners guide)

To your question - as already mentioned before me, you could do Ghillieglade for a week or two and hope to get the desired amount of SES - one run per day per character for non-Club players. However, you should know that upon upgrading your item (from, say, Twistshard to Frostmetal) you get a completely new enigmatic item. It's now free to set stats upon identifying an item, so you can either wait until your next upgrade and pick a new set of stats for free, farm SES or just buy some scrolls off the brokerage (get one first, then check how many you'll actually need). Scrolls can be purchased for these new Entropic Emblems too. Right clicking them opens their shop. For enchanting materials, however, you should use the Metamorphic Emblems shop because it's cheaper. If you have some old enchanting materials such as Masterwork Alkahest, you can dismantle them into Entropic Emblems.

Another thing that is still not in the Rookie Guide above is that you can now unlock a second set of stats for your gear pieces without the need of getting a second item. You just pay a flat (and rather low) fee and you practically get a new item. So, there's no need to have one weapon for PvE and one for PvP for example, or one for warrior tanking and one for warrior dpsing. You can get a second set for both Frostmetal (about 10k per piece) and Stormcry (about 20k per piece). The 2nd set will have random stats, so you must use SES to get the ones you like.

Rerolling is generally only needed if one wants to experiment with weapon or jewellery stats, as it's free to get the stats you desire the first time you identify an item. No need to lock stats with Spellbind and rely on RNG each time you reroll with Master Enigmatic Scroll, or just to RNG in the case of rerolling jewellery with Semi-Enigmatic Scroll. And, as just mentioned above, when one unlocks a 2nd set of stats for their gear piece (weapon, body or light armour). Using SES as a means of trading Entropic Emblems is a less popular use of the former.

Have fun!