Edit relation type

[KaKi87]

Have you read a contributing guide?

• [X] I have read CONTRIBUTING.md
• [X] I have searched the existing requests and didn't find any that were similar
• [X] I have considered creating a pull request instead and want to proceed

Clear and concise description of the problem

After creating a relation, its type cannot be changed.

Suggested solution

Allow changing its type.

Alternative

Having to delete and re-create the type is frustrating.

Additional context

No response