If one gets endorsement in UK , can he apply for stage 2 from any other country,if he is moving on business trips
You can apply for Stage 1 ( Endorsement) from anywhere.
Stage 2 is require you to be in the country of your recidency as it will be qualified as an immigtaion process. It have to be either country of your current Nationality or country where you hold a long-term living residence permit.
If you are based in the UK, then you should double check wether you are elligeble to switch to Tier 1 ET visa from your current immigration status in the UK (e.g. you can switch if you are on Tier 2, however you can not switch if you are on Tier 4 Student, please refere to Home Office guidilines for more details).
Just to join German’s reply - I must say that I applied for both stages not living in the UK. And it does not influence on the result at all. But you must remember that on the Stage 2 you must provide your travel document (passport) for putting there a vignette. This process takes some, in my case it was around 2 weeks.
That is why, you have to be confident in your ability to travel further to your native country or where you need to.
Also, I have recently covered this question about locations in my blog so, perhaps, it will help you too: