//-DYUNQIAN -std=c++14 -O2 -Wall
#include<bits/stdc++.h>

#define ll long long
#define fi first
#define se second
#define mk make_pair

using namespace std;

inline int read(){
    int x=0,f=1;char c=getchar();
    for(;(c<'0'||c>'9');c=getchar()){if(c=='-')f=-1;}
    for(;(c>='0'&&c<='9');c=getchar())x=x*10+(c&15);
    return x*f;
}

const int mod=1e9+7;
int ksm(int x,int y,int p=mod){
    int ans=1;
    for(int i=y;i;i>>=1,x=1ll*x*x%p)if(i&1)ans=1ll*ans*x%p;
    return ans%p;
}
int inv(int x,int p=mod){return ksm(x,p-2,p)%p;}
mt19937 rnd(time(0));
int randint(int l,int r){return rnd()%(r-l+1)+l;}
void add(int &x,int v){x+=v;if(x>=mod)x-=mod;}
void Mod(int &x){if(x>=mod)x-=mod;}

void Assert(bool c,int L=0){if(!c){cout<<"Assertion Failed at "<<L<<endl;exit(0);}}

void cmax(int &x,int v){x=max(x,v);}
void cmin(int &x,int v){x=min(x,v);}

string ch="WB";
void solve(){
	int n=read(),m=read();
	vector<vector<int> >a(n+1);
	for(int i=1;i<=n;i++){
		a[i].resize(m+1);
		for(int j=1;j<=m;j++){
			char c=getchar();while(c!='?'&c!='W'&&c!='B')c=getchar();
			if(c=='W')a[i][j]=0;
			if(c=='B')a[i][j]=1;
			if(c=='?')a[i][j]=-1;
			if(a[i][j]!=-1)a[i][j]^=((i+j)&1);
		}
	}
	queue<pair<int,int> >q;
	auto extend=[&](int x,int y){
		if(x>=2&&y>=2){
			int cnt=0;
			for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)cnt+=(a[x-i][y-j]!=-1);
			if(cnt==3){
				bool chk=1;
				for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)if(a[x-i][y-j]!=-1&&a[x-i][y-j]!=a[x][y])chk=0;
				if(chk){
					for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)if(a[x-i][y-j]==-1)a[x-i][y-j]=(a[x][y]^1),q.push(mk(x-i,y-j));
				}
			}
		}
		if(x>=2&&y<=m-1){
			int cnt=0;
			for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)cnt+=(a[x-i][y+j]!=-1);
			if(cnt==3){
				bool chk=1;
				for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)if(a[x-i][y+j]!=-1&&a[x-i][y+j]!=a[x][y])chk=0;
				if(chk){
					for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)if(a[x-i][y+j]==-1)a[x-i][y+j]=(a[x][y]^1),q.push(mk(x-i,y+j));
				}
			}
		}
		if(x<=n-1&&y>=2){
			int cnt=0;
			for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)cnt+=(a[x+i][y-j]!=-1);
			if(cnt==3){
				bool chk=1;
				for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)if(a[x+i][y-j]!=-1&&a[x+i][y-j]!=a[x][y])chk=0;
				if(chk){
					for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)if(a[x+i][y-j]==-1)a[x+i][y-j]=(a[x][y]^1),q.push(mk(x+i,y-j));
				}
			}
		}
		if(x<=n-1&&y<=m-1){
			int cnt=0;
			for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)cnt+=(a[x+i][y+j]!=-1);
			if(cnt==3){
				bool chk=1;
				for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)if(a[x+i][y+j]!=-1&&a[x+i][y+j]!=a[x][y])chk=0;
				if(chk){
					for(int i=0;i<=1;i++)for(int j=0;j<=1;j++)if(a[x+i][y+j]==-1)a[x+i][y+j]=(a[x][y]^1),q.push(mk(x+i,y+j));
				}
			}
		}
	};
	
	for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)if(a[i][j]!=-1)q.push(mk(i,j));
	if(q.size()==0){
		for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)if(a[i][j]==-1){
			a[i][j]=0,q.push(mk(i,j));goto Yoimiya;
		}
		Yoimiya:;
	}
	while(q.size()){
		auto t=q.front();q.pop();
		extend(t.fi,t.se);
		if(q.size()==0){
			for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)if(a[i][j]==-1){
				a[i][j]=0,q.push(mk(i,j));goto Furina;
			}
			Furina:;
		}
	}
	
	for(int i=1;i<n;i++)for(int j=1;j<m;j++)if(a[i][j]==a[i+1][j]&&a[i+1][j]==a[i][j+1]&&a[i][j+1]==a[i+1][j+1])return puts("NO"),void();
	
	puts("YES");
	for(int i=1;i<=n;i++)for(int j=1;j<=m;j++){
		assert(a[i][j]!=-1);
		a[i][j]^=((i+j)&1);
		cout<<ch[a[i][j]];if(j==m)puts("");
	}
};

signed main(void){

#ifdef YUNQIAN
    freopen("in.in","r",stdin);
#endif

	int tt=read();while(tt--)solve();

    return 0;
}