PAL to NTSC conversion and export options - can anyone help?

Hi all, I'm wondering if anyone can help me.

I'm just about to begin editing a 4 minute video that the client wants delivered to both the USA and UK. The client wants the USA version to be delivered in 29.97i, NTSC, full uncompressed HD. This will be screened to a large conference on a big screen. The UK wants 25p PAL, as I you'd expect. This will just be for online use.

All footage was shot in UHD 29.97 PAL.

My questions are:

(For the USA / screening version)

1. What is a good way to convert 29.97p / PAL to 29.97i / NTSC?

and

(For the UK version)

2. What is a good way to convert 29.97p / PAL to 25p PAL?

Is there anything I need to do to my footage before I begin editing, or is it a case of handling this conversion at the end of the process when I come to export different formats? In Compressor etc.

Any advice at all would be greatly appreciated.

Many thanks,

Peter