Difference between particles に and　は in　あげます/もらいます sentences?


I know 私は田中さんにプレゼントをもらいました means "I received a gift from Mr/Mrs Tanaka" and
私は田中さんにプレゼントをあげました means "I gave a gift to Mr/Mrs Tanaka".

What I'm wondering is, can もらいます・あげます sentences work without the ni particle?

In that case would 田中さんはプレゼントをもらいました mean "Mr/Mrs Tanaka received a gift" and
田中さんはプレゼントをあげました - Mr/Mrs Tanaka gave a gift? Or is it all wrong? And does the
person who receives/gives this to/from Mr/Mrs Tanaka is always implied to be
us, or can it be anybody?




> In that case would 田中さんはプレゼントをもらいました mean "Mr/Mrs Tanaka received a gift"
> and 田中さんはプレゼントをあげました - Mr/Mrs Tanaka gave a gift? Or is it all wrong?

These are correct.

> And does the person who receives/gives this to/from Mr/Mrs Tanaka is always
> implied to be us, or can it be anybody?

It can be anybody. Only seeing these sentences, we can't understand who it is.
Of course, the context may tell us it.




> In that case would 田中さんはプレゼントをもらいました mean "Mr/Mrs Tanaka received a gift"
> and 田中さんはプレゼントをあげました - Mr/Mrs Tanaka gave a gift? Or is it all wrong?

These are correct.

> And does the person who receives/gives this to/from Mr/Mrs Tanaka is always
> implied to be us, or can it be anybody?

It can be anybody. Only seeing these sentences, we can't understand who it is.
Of course, the context may tell us it.

