Singapore Airlines KrisFlyer - Can I use Krisflyer Miles to change Economy class ticket on Lufthansa ?

I'm a Krisflyer member, and was given economy class tickets for Lufthansa.I have plenty of miles. I was thinking of an upgrade, however, the tickets are "low" fare tickets. Which means, they are not refundable nor can I upgrade. But I was wondering, could I change my current tickets to Business Class tickets if I use my miles to pay for Business Class on Lufthansa ?.. Like say an Upgrade from Economy is 25,000 miles. But I can't do an upgrade. To purchase Business Class tickets alone, it would require 130,000 miles. Could I purchase new tickets in exchange of my current tickets using my mile ?... or is it not possible ?....

I'm a Krisflyer member, and was given economy class tickets for Lufthansa.I have plenty of miles. I was thinking of an upgrade, however, the tickets are "low" fare tickets. Which means, they are not refundable nor can I upgrade. But I was wondering, could I change my current tickets to Business Class tickets if I use my miles to pay for Business Class on Lufthansa ?.. Like say an Upgrade from Economy is 25,000 miles. But I can't do an upgrade. To purchase Business Class tickets alone, it would require 130,000 miles. Could I purchase new tickets in exchange of my current tickets using my mile ?... or is it not possible ?....

As you said..your Y tickets are non-refundable so you can't do anything. Either lose them or use them. Even if they were full fare tickets there is no concept of exchanging an award booking for a commercial paid booking.

Although the low Y fare might be non-refundable and non-upgradable to Business Class using miles, you might be able to pay the difference to upfare the ticket to the booking class that allows miles upgrade (e.g. B-class fare). Ask the TA or Lufthansa whether this would be possible.

Beware, however, that an upgradable booking class on almost any airline other than SQ often involves paying amounts very close to a discounted C fare so it might not be worth it.

Although the low Y fare might be non-refundable and non-upgradable to Business Class using miles, you might be able to pay the difference to upfare the ticket to the booking class that allows miles upgrade...
No. not on Lufthansa. They are perfectly inflexible.
..Even if they were full fare tickets there is no concept of exchanging an award booking for a commercial paid booking.
:confused::confused::confused:

If the OP had a full fare ticket, the problem would not arise. And as full fare tickets are not award tickets, they can trivially not be changed from award to revenue tickets....

If they are full fare revenue tickets, then they can easily be upgraded or canceled and be replaced by an award booking.