Is copilot capable of rebuilding an EXISTING PowerPoint presentation based on a referenced POTX

[FSHNL21]

Copilot told me it is possible "Yes, it is indeed possible to use Copilot for M365 in PowerPoint to open an old presentation and prompt Copilot to rebuild it using a specific company template.......After activating Copilot, you'll need to interact with it to specify your requirements. You can prompt Copilot with a command such as: "Rebuild this presentation using the [specific company template]".........

Copilot will then process your request and apply the specified company template to your old presentation. This includes updating the design, layout, and formatting to match the template guidelines.
However, when I try this Copilot in PowerPoint says "Creating a new presentation will replace your existing slides, so you may want to save a copy first. Do you want me to make changes?" 
I think Copilot is not capable of rebuilding existing presentations based on a template. Correct?

[#2]

"Creating a new presentation will replace your existing slides, so you may want to save a copy first. Do you want me to make changes?"

This is just to get confirmation / consent which an end-user has to provide so that Copilot can remove 'texts' from the existing template and add relevant content from the PowerPoint file which has been referred...

[#3]

Hi Ankur, thanks for your reply. Much appreciated. I tried it but did not get the desired result. This is what happened:
My prompt: Change this presentation using the powerpoint template [url to POTX on SharePoint]
Copilot "Creating a new presentation will replace your existing slides, so you may want to save a copy first. Do you want me to make changes?"
My prompt: Yes, please
Copilot "Sorry, I can’t do that just yet. For now, I can only create a presentation from a Word or PDF document. Start typing the name of a file, or copy and paste a link, and I’ll make some slides for you to edit."

I also tried with other wordings like Rebrand, Rebuild.

[#4 · Accepted solution]

Kindly try below steps:
1. Open PowerPoint Template which you want to use for creating a presentation
2. Type Create a presentation from "use the file" then it will prompt a message "Creating a new presentation will replace your existing slides, so you may want to save a copy first. Do you want me to make changes?" Then click yes

[#5]

This is great for creating NEW presentations, however it does not help for rebranding/rebuilding/changing an EXISTING presentation. Tx anyway for your feedback!