Is it possible to move to a new domain without a 301 redirect?
And if so, then how? So that the search engines do not consider the content stolen.
For Google, there is a corresponding tool in the Google Console, click the gear on the right, "Change address", then follow the instructions.
For others SEs, you can write the address of the new site in the Host: directive of your robots file.
But 301 redirect is more reliable, I would recommend using it.
The client's desire is very often the law, but sometimes the client is wrong. If you provide SEO promotion services, it is not always easy to negotiate with the customer. For instance, it is known that when moving to a new domain, in order to transfer weight from the old one, it will be correct to put a 301 redirect from the old one to the new website.
But what if the customer wants to transfer an online store with good positions to a new engine and domain, and leave the old one to work in parallel? In fact, he wants to create a competitor site. How it is worth and what you can do in such a situation, we will analyze in that topic, we will talk about moving from website to site, and creating a second website.
What can be done
When you start a new project, the most painless option to promote it is really to move and put a page redirect (from each page of the old site to the same page of the new one). However, if a situation arises when the customer does not agree to that option and says that a separate website is needed, then care must be taken to:
the new website did not start moving from scratch - to do this, consider buying drop domains. That is, do it not on a zero domain, but on some old one. Or at least glue the old drop, but then you need to pick up a very thematic one;
work hard on building up the authority of a new resource, because the search engine will initially be distrustful and not give traffic, since the site may turn out to be fake, fraudulent, etc.
And in this scenario, investments in promotion will be many times greater than when the site is old or it would be possible to put a 301 redirect. Therefore, if the customer nevertheless insists on that option, focus on the fact that it will be many times more expensive and still less effective. If he is ready for these investments, then it's good, you can work like that.
But usually the explanation of the situation is quite sobering.
How not to fall under the affiliate filter
Another difficulty that will arise: when the second website is launched, the organization on both will be the same and, accordingly, the details will be the same (phone numbers, contacts, etc.). And no one canceled the affiliate filter.
Although it seems that now he has changed and is not quite the same as before. But nevertheless, when two sites of the same organization are in the TOP, the one that is weaker (most likely new) will feel pretty bad. With the old version of the filter, the previous website was not shown at all at the same time as the new one, now the effect seems to be that it is shown, but much lower than the main one.
It is necessary to immediately exclude falling under the affiliate, for which on the new domain it is necessary:
hang new phone numbers - they can be redirected to your main number, but formally they should be different;
place another address;
another name of the organization, logo, etc.
And again, that is a cost and hassle. If the customer is ready for that , then so be it. If not ready, then warn him that:
if you are not ready for investments in principle, then the new website will not immediately move forward very well;
and if you don't want to create that dissimilarity for a new project, then there is a high probability that at first the resource will rise, but at a certain moment it will slow down and begin to sag, or it will sag sharply and stay that way.
Therefore, it is not advisable to do so. The customer should tell and explain all these nuances, perhaps he will listen and will not follow that path.