convert raid 3+1 to raid 0+1

RAID 0+1 ? I think you mean 1+0: you creating a striped meta based on RAID1 symdevs (0+1 means your mirroring 2 RAID0 symdev's which isn't possible on Symm if I'm correct)
Yes, you can get some unused storage or delete unneeded symdevs and create new symdevs in the freed space.

But remember:
1 RAID5 (3+1) symdev of 15GB is actually 20GB of RAW space and you can only create 10GB of RAID1 on that space.

i dont want to make meta. I would like make raid1 without re-make a new bin

Answer is almost the same: convert is not possible, but when you delete a RAID5 (3+1) you only get enough space to create a new RAID1 (mirror) symdev of half the raw space the old RAID5 symdev occupied.

So again: a 15GB RAID5 (3+1) symdev is 20GB of RAW space and when you create a new mirrored symdev in that space, you only will get 10GB. A meta makes more sence, since it occupies more spindels and you'll get better performance than just those 2 spindels.

The unfortunate answer is "not easily" but yes it is possible. First a point of clarification - are you talking Raid-5 3+1 devices or the old (no longer offered - you'd have to be using an older Symmetrix array) Raid-S 3+1 devices? This changes things a little bit because for Raid-S devices you have to reclaim entire Raid-groups which can be difficult at times.

The main issue to consider is that if you want to maintain the same LUN sizes then you need to have more than one Raid device deleted from a physical drive AND they need to have been in sequential order on the disk to get enough space to create your new devices. (i.e. a 9GB Raid-5 device is really 3GB chunks spread across 4 drives while a 9GB Raid-1 device would be 9 GB chunks spread across 2 physical drives.

If you are willing to consider building smaller LUNs and then building metas to get to your ideal size that will work as well, but it can throw-off any schemes for SRDF or BCV replication you have within your box.

Given the complexity and the difficulty in getting some information (i.e. exact symdevice location comes to mind) your best bet is to work with your local EMC SE/CE to see what can be done.

If you are trying to delete a LOT of Raid-5 devices then this may be an easy excercise because you may free-up enough storage to not have to try and squeeze things into place. If that is the case then yes you can easily use ECC to delete these devices and then build the Raid 1 devices you need and then use meta-devices to create your striped LUNs.

Hope this has been helpful.