Depends on the type of reed but from my experience they can take over. My pond doesnt have a liner so I just get in and pull them up but guess if you have a liner you need to be careful. I suppose now would be a good time to get them out rather than when they are in full growth.

Put on some old clothes and start tugging them out slowly. Also inspect the roots for polliwogs ( I love that word), snails and fish which you might wish to throw back in.

In a small pond they are probably in baskets? If so just take out the basket and repot as normal, but using a low fertility compost.

LOL, I like the word Polliwogs too, never heard that name before :o))
I have a question while on the subject of ponds...... when is the best time to sort pond plants out :o))

If you mean rearrange marginal and deep water pond plants, I think the best time is from fall to early spring before new top growth makes a run to the surface.

I'd agree, sort plants , split lilies etc now as they are dormant.
did my pond last week of October.

Oh! I better get it done before any bad weather, I have long rubber gloves to use, they nearly go up to my armpit so I should be ok, My only worry is of falling in, think I may ask next door if I could borrow his scaffold boards LOL