Since they initiated the call I would look at the property and then explain as long as their property is listed you can not talk details.

Get over there . Just be sure that you don't give away your bag of tricks where they go back to the other agent & say 'hey, she will do this'.

Annette Lawrence , Palm Harbor, FL 727-420-4041 Since this seller initiated the call, there is no ethical issue with discussing the property with them and answering their questions. Have them call you when they get a release from the listing or when it expires. Soliciting the listing while it is already listed is a no no.

Since they contacted you, first I would ask them if there were no longer happy with their listing agent and considering leaving.

If yes, I would get the information and forward it to them EXCEPT marketing information - I would withhold marketing techniques, stating once they leave their current agent, I would provide additional information on marketing to make sure the sale is successful

Richard Weeks beat me to the punch!

they asked, and I would look a the land and give my opinion....I would not solicit the listing.... since it's land, my advice would probably create a sale for the other agent....

You were invited; you go. If the homeowner wishes to terminate their current broker relationship; you are not at fault. I would document every action and communication however.

Annette Lawrence , Palm Harbor, FL 727-420-4041 - I think unanimously, we will say, GO and MEET the seller.

There are some great answers here. I have this situation coming up with one of my neighbors. I have a few things I would like to say, but I'll be nice. 

Kenneth J. Jones and others here worded it very well, no point chasing after something that is not available yet.

This has haened to me several times...Checking with the proper people as long as I am invited I am not violating agency

The others have answered.

If they initiate the call, i go, but let them know once expired or no longer listed with xyz, i can discuss value and my marketing plan to get it sold Annette Lawrence , Palm Harbor, FL 727-420-4041 

You have an existing agent which forbids me from discussing the many lucrative options one can take to realize maximum return or potential. 

Go see it.  Document that they contacted you first, so other Agent won't cry COE violation.

Maybe, but first: why aren't you happy?
If there's a good reason, sure and we can discuss the terms of a future listing. If it looks like XYZ is doing a decent job . . . give XYZ a chance, will ya?

how long til;l it expires!

I have looked at your property and will keep it in consideration for my Buyers.  I think it would be advantageous to reduce your price, since it is a bit overpriced for the market.  They won't like to hear that and may not offer the listing to you; which sounds fine to you!

I would look at the property for them and make a listing of what I would do.  I'd find out when the listing expires and tell them that "I can't step on another agent's toes and my professional ethics won't allow me to discuss what I would do differently while someone else has the listing.  Once the listing expires I would be happy to discuss my marketing plan."  I'd also add in that "if the agent wants to co-list the house with me, I'd be happy to help out sooner."

I see your replies to a few of the answers.  With an owner in another reality, I'd stick with "I can't discuss while the listing is owned by someone else" and I'd not take the listing if it expires unless the owner "came back to this reality" and agreed to certain steps.

They would have to get a release in writing from XYZ company and their listing agent first.  Then I would talk to them.

They called you, I would talk to them and see what is going on. 

I try to be careful not get into a situation where someone files compliants against you.  I remind them they need to cancel the contract before we do any serious talks.

You can offer advice on the unlisted property but not on the listed one. I would be very careful to keep accurate recordes of phone calls and emails, etc, to prevent an ethics complaint.

Richard Weeks and Michael Setunsky have the answer as to what I would do.

Check it out since you were contact. Keep careful notes, all emails just in case. Don't share everything until the relationship is clear and formalized

I would probably go look at the property and tell her I can't discuss a marketing strategy while she is under contract with another agency.  This would have to be done in a way that could not be construed as "soliciting the listing" while under contract.  

I worked in a small market and knew all the agents.  If it was someone I knew well and respected I might try to approach them with some ideas.  

In the end... as with all things... it depends.  

I would look at it and tell them what I would do, and even list it with listing to take effect when current listing expires or is withdrawn.