This can differ from provider to provider, but in general, we will start a transfer for you and request the previous owner of the domain to change the IPS tags. We would suggest that you find the help page with your domain provider to get the answer to this or get in touch and we can take a look for you.

123 Reg:
https://www.123-reg.co.uk/support/domains/transferring-third-party-domain-names-to-123-reg/

GoDaddy
https://uk.godaddy.com/help/about-uk-domains-5854

Names.co.uk
https://www.names.co.uk/support/1153-transfer_a_domain_away_from_namescouk.html

1&1 (now Ionos)
https://www.ionos.co.uk/help/domains/transferring-your-domain-away-from-11-ionos-to-another-provider/transferring-a-uk-domain-from-11-ionos-to-another-provider-changing-the-ips-tag/

Fasthosts
https://help.fasthosts.co.uk/app/answers/detail/a_id/1838/~/transferring-domains-away-from-fasthosts