Please be careful, looking into this.
I think only we can call our own spirits back (which I'll call it here). It's something other people can maybe help us with but they can't do it for us. I would be really, really, really wary of anyone claiming they can do it for you. This is not to do with how sincere they are - they might be, and they might not be - but so much could go badly. And personally, I don't think this is a valid approach.
Do you know David Chetlahe Paladin's story? If not, I recommend googling it. This is my image of calling one's spirit back. After various ordeals, he returned to his Navajo tribe broken physically, mentally and spiritually. The elders carried out a ritual which forced him to choose between becoming present and whole again, or giving up completely. He chose to call his spirit back.
Two points about the story.
The first is that the elders didn't retrieve his soul for him. They didn't tell him how to, and they didn't take him through any steps. They merely faced him with the necessity for him to do it or remain lost. If anyone's seriously looking into this, they're probably already aware of that need. I'm not convinced that anyone else can add much, or can genuinely help with this process, through dramatic ceremonies, rituals, weekend retreats, shamanic treatments or the like.
The second point is - are you a Navajo? I'm not being flippant, if you're a Navajo (or were brought up in whatever tradition is being drawn on) then this won't apply. If you're considering something that isn't a tradition in your own cultural background, I think it's good to ask yourself some questions:
- How much genuine, full understanding do you have of the meaning and implications of what's being offered?
- Do you know enough to assess it and make an informed judgement about it?
- Can you tell if it's an ethical and responsible way to use the tradition?
- Can you tell if it's likely to be safe for you?
- Are you attracted to it because it's outside your usual experiences, and you hope it can work in some magical way, when you wouldn't expect the same from a tradition you're more familiar with?
- If it really is powerful and can have an effect of any sort, do you want to actually put yourself/your soul in the hands of someone you don't know using a method you know little about?
There are two ways that I think other people can help us in the process of calling our spirits back.
One way is by encouraging and guiding us. That doesn't have to be religion, or even something like meditation, although it can be. It doesn't have to be from your own cultural tradition either. It could be shamanism. My personal view, though, is that it needs to be something that doesn't promise dramatic magic (including in the shamanic sense) and doesn't promise to do anything for you other than help you to find your own way.
The other is that I think some rituals and traditions can give us support and help in the process. For example, I've had a blessing from a monk at a Buddhist temple. I did this knowing a lot about Buddhism and what to expect. I knew that the blessing could be powerful, but that the power wasn't a magical one, it wasn't going to suddenly change everything, it would be completely safe and the monk wasn't retrieving anything for me. He was only helping me to connect to energies/spirituality or whatever you want to call it, that I needed to connect to for myself.