Hi All,
First time posting so hoping I share enough information to make sense of my requirement.
I have a SharePoint List with many columns of Number format. I was able to use HTTP Request to POST the columns on a Loop just increasing a number used within the Title and InternalName, which worked well.
However, the column format now needs to be changed to Choice and I am struggling to use the PATCH or PUT methods to change the type of field, add choices etc. List not yet storing any data.
Image shows how I first attempted this, which works to create with POST method but not update using PATCH.
Please can someone confirm if we are you able to update the existing field properties using the HTTP request or only create new fields (and if so, where I am going wrong)? If I can get the method working, the idea is to increment through iLoop variable for required interval and edit each of the columns, instead of manually changing them.

I've read a few responses from @Expiscornovus and others in this space but nothing that covers updating the properties of the columns in a List rather than the items themselves.
Thanks for any suggestions.