It's not in the rules so we can't have it I'm afraid. It also depends how long ago you mean. A couple of people who had been playing since the year dot stopped playing when someone changed the rules recently to allow extra letters. I thought that was such a shame but if you want to change the rules what do others think?

I suppose I prefer the proper rules. Rules can't really be changed on a whim because noone would know what they were supposed to be doing. I mean perhaps I could add 2 letters or take 2 away.It wouldn't be the same game then would it? Or even, is it now okay to add 3 letters? Part of the game is the challenge of adhering to the rules otherwise it's pointless.

This is just my opinion though. I'm not claiming to be God! 

Annie_Boxed_In:

I thought people were quite frequently changing one or two letters, so I didn't think it really mattered

neither did I tbh, and I've noticed that too (people changing 2) . . . . . .  and I'm perhaps guilty of inadvertently 'rule breaking' myself . . . . . .personally I think that if it's impossible to create a new word by sticking to the rules, then some latitude should be allowed . . . it's been done in the past . . . . . BUT in the particular instance of changing FLEET to TRIFLE, then I think LEFT or FELT could have done the job

but just to clarify upon the rules;

change one and add/subtract one?

and/or

change one or add/subtract one?

It's - change one, add one or take one away.

ShowerGel:

It's - change one, add one or take one away.

Ooops crossed posts  - ok