I was asked to explain why relying on can not be used instead of depending on in the following sentence - but my explanation is, well, not so hot - I am relying on you to help me! Thanks

I would like a different ring tone on my mobile depending on who is calling me.
depending on=according to.
relying on=depend on with full trust or confidence.

So, in your example, depending on is correct, relying on is wrong.


In the given sentence, 'depending on' functions as 'according to'.

I have set the ringtone according to the people who call me.

Somebody/something relies on somebody/something for some self-interest/purpose.
We rely on trees for oxygen.(depend on)
We rely on you to give a clear explanation. (trust/ have faith)
Teachers: We supply a list of EFL job vacancies
thanks for the explanation
and thank you too