Hi Sandy, the first thing is to talk to a real estate agent and go over all your options. It is hard to understand just what your requirements are in that short sentence. Do you need to sell first in order to buy, where are you relocating to, how much is your home worth, will it sell fast, etc. A consultation is free and it is only an email or phone call away. You then could make a good decision on your next course of action.
What you could do is put a contingency clause in your contract. Depending on where you are located your local Realtor will have a contract that may have that clause in it already. It allows you to place your home on the market for sale but, put in an offer for another home under the "contingency" your home is going to be sold. A lot of times when someone puts that contingency in their contract they will also put "first right of refusal" in there as well. This would allow other offers to come in on the home you are wanting to purchase but, giving first option on the property. If someone came in with a full price offer cash in hand or could close immediately they would ask you if you wanted to purchase at that time regardless of your home being sold. There are many options when you have a home to sell. If you need more information feel free to email me.