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What semantic notions underlie “to exchange” (PIE *meyth₂-)   🢂  “to give, bestow”  🡺  “to let go, send”  (Proto-Italic *meitō)? 

[Wiktionary](https://en.wiktionary.org/wiki/mitto#Etymology_2) asservates 

>May be for _*mītō_ (with lengthening of the consonant; compare [mitāt](https://en.wiktionary.org/wiki/mitat#Latin)),    
from Proto-Italic _*meitō_,   
from Proto-Indo-European [_*meyth₂-_](https://en.wiktionary.org/wiki/Reconstruction:Proto-Indo-European/meytH-) (“to exchange”), an extension of the root [_*mey-_](https://en.wiktionary.org/wiki/Reconstruction:Proto-Indo-European/mey-).    
**[1.]** From the original meaning “to exchange”    
 **[2.]** a [semantic shift](https://en.wiktionary.org/wiki/semantic_shift) occurred to “to give, bestow”     
 **[3.]** and then "to let go, send”.

Like a math problem — Can you please show the steps for, and expatiate the _TWO_ semantic shifts from, 1 🡺  2 🡲 3?