On my Tablet, a tap-and-hold gets me choices - of those,
copy link text gets abbreviated link with three dots BUT
copy link address gets the full link -
This is what one wants to convert between Ancestry and AncestryLibrary
Copy the full link. Paste it somewhere you can edit it.
I am told on a PC, do a CTRL-click to bring up a small 'context' menu, selecting to copy the link address (a.k.a. the full text of the embedded URL).
Then you can paste the copied link
To go from Ancestry to AncestryLibrary:
See where the address has "ancestry.com" [no quotation marks]
stick your cursor right between. The "y" and the dot -- then type "library" [no quotation marks]
So now that section of address reads "ancestrylibrary.com" [no quotation marks]
Copy and use the full modified link
Going the other direction, just delete the word "library" from "ancestrylibrary.com" [no quotation marks]