Cleaning up / formatting verbatim quotations

Solution 1:

In Section 13.7, "Permissible changes to punctuation, capitalization, and spelling," the Chicago Manual of Style says:

Although in a direct quotation the wording should be reproduced exactly, the following changes are generally permissible to make a passage fit into the syntax and typography of the surrounding text.

...

Obvious typographic errors may be corrected silently (without comment or sic; see 13.59), unless the passage quoted is from an older work or a manuscript source where idiosyncrasies of spelling are generally preserved. If spelling and punctuation are modernized or altered for clarity, readers must be so informed in a note, in a preface, or elsewhere.

The sort of correction that you're proposing is covered by this guideline. For a more extensive paraphrase, it would probably be best to quote the person indirectly.

This type of editing is generally referred to as formatting a quotation; the MLA Style Guide has a number of guidelines for formatting quotations to indicate elided or added text.

Solution 2:

These matters are usually settled by a publisher’s house style. Some will have you write “[sic]” everywhere, some will have you annotate with parentheses, and some will let you freely edit, so long as you preserve the “spirit” of the quote. There are questions on this site about “[sic]” and how to use it correctly.

In the particular case you gave, all you’re doing is expanding abbreviations, so you are, in a sense, still quoting verbatim:

He said, “I’m looking forward to seeing more global exchange-traded funds”.

Many publications include a disclaimer that interviews, quotations, &c. may be edited for length, content, and other pressures of publishing. If that makes you uncomfortable, you can always just rephrase to make the quotation implicit: