If, as speculated here, "the candidate (for a merger) would want more shares than the current a/s could accommodate," there are arguably two ways to proceed. Raise A/S and issue additional shares or reverse split O/S thereby leaving A/S intact yet allowing additional share issuance.
Given the merger scenario, I'm inclined to expect a reverse split as means of funding it. A reverse split achieves two goals. R/S provides needed share dilution and simultaneously increases stock price to a level more suitable for higher level listing.